Difference between revisions of "Applications-of-GeoGebra/C2/Roots-of-Polynomials/English"

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Line 4: Line 4:
  
 
|-
 
|-
−
| | '''Slide Number 1'''
+
|| '''Slide Number 1'''
  
 
'''Title Slide'''
 
'''Title Slide'''
−
| | Welcome to this tutorial on '''Roots of Polynomials'''.
+
|| Welcome to this tutorial on '''Roots of Polynomials'''.
 
|-
 
|-
−
| | '''Slide Number 2'''
+
|| '''Slide Number 2'''
  
 
'''Learning Objectives'''
 
'''Learning Objectives'''
−
| | In this tutorial, we will learn:  
+
|| In this tutorial, we will learn:  
−
*To plot graphs of '''polynomial''' equations
+
* To plot graphs of '''polynomial''' equations
  
−
*About '''complex numbers''', '''real''' and '''imaginary roots'''
+
* About '''complex numbers''', '''real''' and '''imaginary roots'''
  
−
*To find '''extrema''' and '''inflection points'''
+
* To find '''extrema''' and '''inflection points'''
 
|-
 
|-
−
| | '''Slide Number 3'''
+
|| '''Slide Number 3'''
 
'''Pre-requisites'''
 
'''Pre-requisites'''
  
 
'''www.spoken-tutorial.org'''
 
'''www.spoken-tutorial.org'''
−
| | To follow this tutorial, you should be familiar with  
+
|| To follow this tutorial, you should be familiar with  
−
*'''GeoGebra''' interface
+
* '''GeoGebra''' interface
  
 
*Basics of '''coordinate system'''
 
*Basics of '''coordinate system'''
Line 32: Line 32:
 
*If not, for relevant tutorials, please visit our website.
 
*If not, for relevant tutorials, please visit our website.
 
|-
 
|-
−
| | '''Slide Number 4'''
+
|| '''Slide Number 4'''
  
 
'''System Requirement'''
 
'''System Requirement'''
−
| | Here I am using:
+
|| Here I am using:
  
 
*'''Ubuntu Linux''' OS version 14.04
 
*'''Ubuntu Linux''' OS version 14.04
Line 41: Line 41:
 
*'''GeoGebra 5.0.388.0-d'''
 
*'''GeoGebra 5.0.388.0-d'''
 
|-
 
|-
−
| |  
+
||  
−
| | Let us begin with the '''binomial theorem'''.
+
|| Let us begin with the '''binomial theorem'''.
 
|-
 
|-
−
| | '''Slide Number 5'''
+
|| '''Slide Number 5'''
  
 
'''Binomial Theorem'''
 
'''Binomial Theorem'''
Line 55: Line 55:
  
 
Reminder: ''<sup>n</sup>C<sub>1</sub> = n!/[1! (n-1)!]''
 
Reminder: ''<sup>n</sup>C<sub>1</sub> = n!/[1! (n-1)!]''
−
| | '''''a''''' and '''''b''''' are '''real numbers'''.
+
|| '''''a''''' and '''''b''''' are '''real numbers'''.
  
−
'''index''' '''''n''''' is a positive integer.  
+
'''index''' '''''n''''' is a positive integer.  
  
 
'''''r''''' lies between 0 and '''''n'''''.  
 
'''''r''''' lies between 0 and '''''n'''''.  
Line 63: Line 63:
 
'''Binomial theorem''' states that '''''a''''' plus '''''b''''' raised to '''''n''''' can be expanded as shown.  
 
'''Binomial theorem''' states that '''''a''''' plus '''''b''''' raised to '''''n''''' can be expanded as shown.  
 
|-
 
|-
−
| | '''Slide Number 6'''
+
|| '''Slide Number 6'''
  
 
'''Quadratic Equations and Roots'''
 
'''Quadratic Equations and Roots'''
  
−
*A second degree polynomial, '''y =''' '''''a''''' '''x<sup>2</sup>+''' '''''b''''' '''x+''' '''''c''''' has roots  
+
* A second degree polynomial, '''y =''' '''''a''''' '''x<sup>2</sup>+''' '''''b''''' '''x+''' '''''c''''' has roots  
  
−
*'''x=-''' '''''b''''' '''± sqrt{(''' '''''b''''' '''<sup>2</sup>-4''' '''''ac)/2a''''' '''}'''  
+
* '''x=-''' '''''b''''' '''± sqrt{(''' '''''b''''' '''<sup>2</sup>-4''' '''''ac)/2a''''' '''}'''  
−
 
+
−
*where '''▲=''' '''''b<sup>2</sup>-4ac'''''
+
* where '''▲=''' '''''b<sup>2</sup>-4ac'''''
  
−
*When ▲< 0, roots are complex
+
* When ▲< 0, roots are complex
  
−
*When ▲=0, roots are real and equal
+
* When ▲=0, roots are real and equal
  
−
*When ▲>0, roots are real and unequal
+
* When ▲>0, roots are real and unequal
−
| | '''Quadratic Equations and Roots'''
+
|| '''Quadratic Equations and Roots'''
  
 
A '''2<sup>nd</sup> degree polynomial''', '''y equals''' '''''a''''' '''x squared plus''' '''''b''''' '''x plus''' '''''c''''' has '''roots''' given by values of '''''x'''''.
 
A '''2<sup>nd</sup> degree polynomial''', '''y equals''' '''''a''''' '''x squared plus''' '''''b''''' '''x plus''' '''''c''''' has '''roots''' given by values of '''''x'''''.
Line 92: Line 92:
 
When '''Delta''' is greater than 0, '''roots''' are '''real''' and unequal
 
When '''Delta''' is greater than 0, '''roots''' are '''real''' and unequal
 
|-
 
|-
−
| | '''Slide Number 7'''
+
|| '''Slide Number 7'''
  
 
'''Quadratic Equations and Roots'''
 
'''Quadratic Equations and Roots'''
  
−
*When roots are real, '''''ax<sup>2</sup>+b''''' '''x+''' '''''c''''' '''=0''' has extremum '''(x<sub>v</sub>, y<sub>v</sub>)'''
+
* When roots are real, '''''ax<sup>2</sup>+b''''' '''x+''' '''''c''''' '''=0''' has extremum '''(x<sub>v</sub>, y<sub>v</sub>)'''
  
−
*'''x<sub>v</sub> = -''' '''''b/2a''''' and '''y<sub>v</sub>=''' '''''a''''' '''x<sub>v</sub><sup>2</sup>+''' '''''b''''' '''x<sub>v</sub>+''' '''''c'''''
+
* '''x<sub>v</sub> = -''' '''''b/2a''''' and '''y<sub>v</sub>=''' '''''a''''' '''x<sub>v</sub><sup>2</sup>+''' '''''b''''' '''x<sub>v</sub>+''' '''''c'''''
−
| | '''Quadratic Equations and Roots'''
+
|| '''Quadratic Equations and Roots'''
  
 
When '''roots''' are '''real''', '''''ax''''' '''squared plus''' '''''b x''''' '''plus''' '''''c''''' equals 0 has '''extremum''' '''''xv''''' '''comma''' '''''yv'''''
 
When '''roots''' are '''real''', '''''ax''''' '''squared plus''' '''''b x''''' '''plus''' '''''c''''' equals 0 has '''extremum''' '''''xv''''' '''comma''' '''''yv'''''
Line 105: Line 105:
 
'''''xv''''' equals '''minus''' '''''b''''' '''divided by 2''' '''''a''''' and '''''yv''''' '''equals''' '''''axv''''' '''squared plus''' '''''bxv''''' '''plus''' '''''c'''''
 
'''''xv''''' equals '''minus''' '''''b''''' '''divided by 2''' '''''a''''' and '''''yv''''' '''equals''' '''''axv''''' '''squared plus''' '''''bxv''''' '''plus''' '''''c'''''
 
|-
 
|-
−
| | Show the '''GeoGebra''' window.
+
|| Show the '''GeoGebra''' window.
−
| | I have already opened the '''GeoGebra''' interface.
+
|| I have already opened the '''GeoGebra''' interface.
 
|-
 
|-
−
| | Click on '''View''' >> select '''CAS'''.
+
|| Click on '''View''' >> select '''CAS'''.
  
−
| | Click on '''View''' tool and select '''CAS''' to open the '''CAS''' view.
+
|| Click on '''View''' tool and select '''CAS''' to open the '''CAS''' view.
 
|-
 
|-
−
| | In line 1 in '''CAS view''', type '''f(x):=x^2-2x-3''' >> press '''Enter'''.
+
|| In line 1 in '''CAS view''', type '''f(x):=x^2-2x-3''' >> press '''Enter'''.
−
| | In line 1 in '''CAS''' view, type the following line.
+
|| In line 1 in '''CAS''' view, type the following line.
  
 
'''f x''' in parentheses '''colon equals x caret 2 minus 2 space x minus 3'''.  
 
'''f x''' in parentheses '''colon equals x caret 2 minus 2 space x minus 3'''.  
Line 123: Line 123:
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Drag boundary to see '''Algebra''' view properly.  
+
|| Drag boundary to see '''Algebra''' view properly.  
−
| | Drag boundary to see '''Algebra''' view properly.  
+
|| Drag boundary to see '''Algebra''' view properly.  
 
|-
 
|-
−
| | Point to the '''equation f(x)''' appearing in '''Algebra''' view.
+
|| Point to the '''equation f(x)''' appearing in '''Algebra''' view.
  
 
Point to '''exponent''' 2 in '''f(x)'''.
 
Point to '''exponent''' 2 in '''f(x)'''.
−
| | Observe the '''equation f of x''' in '''Algebra''' view.
+
|| Observe the '''equation f of x''' in '''Algebra''' view.
  
 
The '''degree''' of this '''quadratic polynomial f of x''' is 2.
 
The '''degree''' of this '''quadratic polynomial f of x''' is 2.
 
|-
 
|-
−
| | Drag boundary to see '''Graphics''' view properly.  
+
|| Drag boundary to see '''Graphics''' view properly.  
−
| | Drag boundary to see '''Graphics''' view properly.  
+
|| Drag boundary to see '''Graphics''' view properly.  
 
|-
 
|-
−
| | Click in '''Graphics''' view to see '''Graphics View''' toolbar.  
+
|| Click in '''Graphics''' view to see '''Graphics View''' toolbar.  
−
| | Click in '''Graphics''' view to see '''Graphics View''' toolbar.  
+
|| Click in '''Graphics''' view to see '''Graphics View''' toolbar.  
 
|-
 
|-
−
| | '''Move Graphics View'''>> click on '''Zoom Out'''
+
|| '''Move Graphics View'''>> click on '''Zoom Out'''
−
| | Under '''Move Graphics View''', click on '''Zoom Out''' tool.  
+
|| Under '''Move Graphics View''', click on '''Zoom Out''' tool.  
 
|-
 
|-
−
| |Click in '''Graphics''' view >> minimum '''vertex''' of '''parabola f'''.  
+
||Click in '''Graphics''' view >> minimum '''vertex''' of '''parabola f'''.  
  
−
| |Click in '''Graphics''' view to see the minimum '''vertex''' of '''parabola f'''.  
+
||Click in '''Graphics''' view to see the minimum '''vertex''' of '''parabola f'''.  
 
|-
 
|-
−
| | Click on '''Move Graphics View''' tool >> click in '''Graphics''' background.   
+
|| Click on '''Move Graphics View''' tool >> click in '''Graphics''' background.   
−
| | Click on '''Move Graphics View''' tool and click in '''Graphics''' background.  
+
|| Click on '''Move Graphics View''' tool and click in '''Graphics''' background.  
 
|-
 
|-
 
| |Hand symbol appears >> drag '''Graphics''' view to see parabola '''f'''.
 
| |Hand symbol appears >> drag '''Graphics''' view to see parabola '''f'''.
 
| |When hand symbol appears, drag '''Graphics''' view so you can see parabola '''f'''.  
 
| |When hand symbol appears, drag '''Graphics''' view so you can see parabola '''f'''.  
 
|-
 
|-
−
| | Drag boundaries  
+
|| Drag boundaries  
−
| | Drag boundaries to see '''CAS''' view properly.  
+
|| Drag boundaries to see '''CAS''' view properly.  
 
|-
 
|-
−
| | Type '''Root(f)''' in line 2 of '''CAS''' view >> press '''Enter'''.
+
|| Type '''Root(f)''' in line 2 of '''CAS''' view >> press '''Enter'''.
−
| | In line 2 of '''CAS''' view, type '''Root f''' in parentheses.  
+
|| In line 2 of '''CAS''' view, type '''Root f''' in parentheses.  
  
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Point to '''roots''' in '''CAS''' view.
+
|| Point to '''roots''' in '''CAS''' view.
−
| | The '''roots''' appear below, in the same box, in curly brackets.  
+
|| The '''roots''' appear below, in the same box, in curly brackets.  
 
|-
 
|-
−
| | Point to '''roots''' in '''Graphics''' view.
+
|| Point to '''roots''' in '''Graphics''' view.
−
| | Note that these are the '''x-intercepts''' of parabola '''f''' in '''Graphics''' view.
+
|| Note that these are the '''x-intercepts''' of parabola '''f''' in '''Graphics''' view.
 
|-
 
|-
−
| | Type '''Extremum(f)''' in line 3 of '''CAS''' view >> press '''Enter'''.
+
|| Type '''Extremum(f)''' in line 3 of '''CAS''' view >> press '''Enter'''.
−
| | In line 3 of '''CAS''' view, type '''Extremum f''' in parentheses.
+
|| In line 3 of '''CAS''' view, type '''Extremum f''' in parentheses.
  
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Point to '''extremum''' in '''CAS''' view.
+
|| Point to '''extremum''' in '''CAS''' view.
−
| | The '''extremum''' appears below, in the same box, in curly brackets.
+
|| The '''extremum''' appears below, in the same box, in curly brackets.
 
|-
 
|-
−
| | Note that this is the minimum '''vertex''' of parabola '''f''' in '''Graphics''' view.  
+
|| Note that this is the minimum '''vertex''' of parabola '''f''' in '''Graphics''' view.  
−
| | Note that this is the minimum '''vertex''' of parabola '''f''' in '''Graphics''' view.  
+
|| Note that this is the minimum '''vertex''' of parabola '''f''' in '''Graphics''' view.  
 
|-
 
|-
−
| | In line 4 in '''CAS''' view, type '''g(x):=x^2+5x+10''' >> press '''Enter'''.
+
|| In line 4 in '''CAS''' view, type '''g(x):=x^2+5x+10''' >> press '''Enter'''.
−
| | In line 4 in '''CAS''' view, type the following line.
+
|| In line 4 in '''CAS''' view, type the following line.
  
 
'''g x''' in parentheses '''colon equals x caret 2 plus 5 space x plus 10'''.  
 
'''g x''' in parentheses '''colon equals x caret 2 plus 5 space x plus 10'''.  
Line 184: Line 184:
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Drag boundary to see '''Algebra''' view properly.  
+
|| Drag boundary to see '''Algebra''' view properly.  
  
 
Point to the '''equation g(x)''' appearing in '''Algebra''' view.
 
Point to the '''equation g(x)''' appearing in '''Algebra''' view.
−
| | Drag boundary to see '''Algebra''' view properly.  
+
|| Drag boundary to see '''Algebra''' view properly.  
  
 
Observe the '''equation g of x''' in '''Algebra''' view.
 
Observe the '''equation g of x''' in '''Algebra''' view.
 
|-
 
|-
−
| | Drag boundary to see '''Graphics''' view properly.  
+
|| Drag boundary to see '''Graphics''' view properly.  
−
| | Drag boundary to see '''Graphics''' view properly.  
+
|| Drag boundary to see '''Graphics''' view properly.  
 
|-
 
|-
−
| | Uncheck '''f of x''' in '''CAS''' view.
+
|| Uncheck '''f of x''' in '''CAS''' view.
  
 
Note that this also unchecks it in '''Algebra''' view and hides parabola '''f''' in '''Graphics''' view.  
 
Note that this also unchecks it in '''Algebra''' view and hides parabola '''f''' in '''Graphics''' view.  
−
| | Uncheck '''f of x''' in '''CAS''' view.
+
|| Uncheck '''f of x''' in '''CAS''' view.
  
 
Note that this also unchecks it in '''Algebra''' view and hides parabola '''f''' in '''Graphics''' view.  
 
Note that this also unchecks it in '''Algebra''' view and hides parabola '''f''' in '''Graphics''' view.  
 
|-
 
|-
−
| | Click and drag '''Graphics''' view so you can see parabola '''g'''.  
+
|| Click and drag '''Graphics''' view so you can see parabola '''g'''.  
−
| | Click in and drag '''Graphics''' view so you can see parabola '''g'''.  
+
|| Click in and drag '''Graphics''' view so you can see parabola '''g'''.  
 
|-
 
|-
−
| | Again, drag boundary to see '''CAS''' view properly.  
+
|| Again, drag boundary to see '''CAS''' view properly.  
−
| | Again, drag boundary to see '''CAS''' view properly.  
+
|| Again, drag boundary to see '''CAS''' view properly.  
 
|-
 
|-
−
| | Type '''Root(g)''' in line 5 of '''CAS''' view >> press '''Enter'''.
+
|| Type '''Root(g)''' in line 5 of '''CAS''' view >> press '''Enter'''.
−
| | In line 5 of '''CAS''' view, type '''Root g''' in parentheses.  
+
|| In line 5 of '''CAS''' view, type '''Root g''' in parentheses.  
  
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Point to empty curly brackets for '''roots''' in '''CAS''' view.
+
|| Point to empty curly brackets for '''roots''' in '''CAS''' view.
−
| | Empty curly brackets appear below.  
+
|| Empty curly brackets appear below.  
  
 
Parabola '''g''' does not have any '''real roots''' as it does not intersect '''x axis''' at all.  
 
Parabola '''g''' does not have any '''real roots''' as it does not intersect '''x axis''' at all.  
Line 219: Line 219:
 
'''Roots''' are said to be '''complex'''.  
 
'''Roots''' are said to be '''complex'''.  
 
|-
 
|-
−
| | Type '''Extremum(g)''' in line 6 of '''CAS '''view >> press '''Enter'''.
+
|| Type '''Extremum(g)''' in line 6 of '''CAS '''view >> press '''Enter'''.
−
| | In line 6 of '''CAS''' view, type '''Extremum g''' in parentheses.
+
|| In line 6 of '''CAS''' view, type '''Extremum g''' in parentheses.
  
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Point to '''extremum''' in '''CAS''' view.
+
|| Point to '''extremum''' in '''CAS''' view.
−
| | The '''extremum''' appears below, in the same box, in curly brackets.  
+
|| The '''extremum''' appears below, in the same box, in curly brackets.  
 
|-
 
|-
−
| | Note that this is the minimum '''vertex''' of parabola '''g''' in '''Graphics''' view.  
+
|| Note that this is the minimum '''vertex''' of parabola '''g''' in '''Graphics''' view.  
−
| | Note that this is the minimum '''vertex''' of parabola '''g''' in '''Graphics''' view.  
+
|| Note that this is the minimum '''vertex''' of parabola '''g''' in '''Graphics''' view.  
 
|-
 
|-
−
| | Point to '''Evaluate''' tool.  
+
|| Point to '''Evaluate''' tool.  
  
 
Point to '''extremum''' in form of '''fractions'''.  
 
Point to '''extremum''' in form of '''fractions'''.  
−
| | While '''Evaluate''' tool is highlighted in '''CAS View''' toolbar, the '''extremum''' appears as '''fractions'''.  
+
|| While '''Evaluate''' tool is highlighted in '''CAS View''' toolbar, the '''extremum''' appears as '''fractions'''.  
  
 
'''Minus five divided by 2 comma 15 divided by 4'''.
 
'''Minus five divided by 2 comma 15 divided by 4'''.
 
|-
 
|-
−
| | Click on the '''extremum''' in line 6 and click on '''Numeric''' tool.  
+
|| Click on the '''extremum''' in line 6 and click on '''Numeric''' tool.  
  
 
Point to '''extremum''' in form of '''decimals'''.  
 
Point to '''extremum''' in form of '''decimals'''.  
−
| | In line 6, click on the '''extremum''' and click on '''Numeric''' tool.  
+
|| In line 6, click on the '''extremum''' and click on '''Numeric''' tool.  
  
 
The '''extremum '''now appears in '''decimal''' form.  
 
The '''extremum '''now appears in '''decimal''' form.  
Line 246: Line 246:
 
'''Minus 2 point 5 comma 3 point 7 5'''.
 
'''Minus 2 point 5 comma 3 point 7 5'''.
 
|-
 
|-
−
| |  
+
||  
−
| | Let us look at '''complex numbers'''.  
+
|| Let us look at '''complex numbers'''.  
 
|-
 
|-
−
| | '''Slide Number 8'''
+
|| '''Slide Number 8'''
  
 
'''Complex numbers, XY plane'''
 
'''Complex numbers, XY plane'''
  
  
−
*A '''complex number''' is expressed as '''''z = a + bi''''': where ''''''a'''''' = real part, ‘'''''bi’''''' = '''imaginary '''part, and '''a''' and '''b''' are constants.
+
* A '''complex number''' is expressed as '''''z = a + bi''''': where ''''''a'''''' = real part, ‘'''''bi’''''' = '''imaginary '''part, and '''a''' and '''b''' are constants.
  
−
*'''Imaginary number, ''i'' '''= sqrt{-1}
+
* '''Imaginary number, ''i'' '''= sqrt{-1}
  
  
−
*In the '''XY plane''', '''''a + bi''''' is point ('''a, b''').
+
* In the '''XY plane''', '''''a + bi''''' is point ('''a, b''').
  
  
−
*In the '''complex plane''', '''x axis''' = '''real axis''', '''y axis''' = '''imaginary axis'''.
+
* In the '''complex plane''', '''x axis''' = '''real axis''', '''y axis''' = '''imaginary axis'''.
−
| | '''Complex numbers, XY plane'''
+
|| '''Complex numbers, XY plane'''
  
 
A '''complex number''' is expressed as '''''z''''' '''equals''' '''''a''''' '''plus''' '''''bi'''''.
 
A '''complex number''' is expressed as '''''z''''' '''equals''' '''''a''''' '''plus''' '''''bi'''''.
Line 279: Line 279:
 
In the '''complex plane''', '''x axis''' is called '''real axis, y axis''' is called '''imaginary axis'''.
 
In the '''complex plane''', '''x axis''' is called '''real axis, y axis''' is called '''imaginary axis'''.
 
|-
 
|-
−
| | '''Slide Number 9'''
+
|| '''Slide Number 9'''
  
 
'''Complex numbers, complex plane'''
 
'''Complex numbers, complex plane'''
  
−
*In '''complex plane''', '''''z''''' is a '''vector''' with '''real axis coordinate''' '''''a''''' and '''imaginary axis coordinate''' '''''b'''''
+
* In '''complex plane''', '''''z''''' is a '''vector''' with '''real axis coordinate''' '''''a''''' and '''imaginary axis coordinate''' '''''b'''''
  
  
−
*Length of the '''vector''' '''''z''''' = |'''''z'''''| = '''''r'''''
+
* Length of the '''vector''' '''''z''''' = |'''''z'''''| = '''''r'''''
  
  
−
*'''''r''''' '''= sqrt (a<sup>2</sup>+b<sup>2</sup>) (Pythagoras’ theorem)'''
+
* '''''r''''' '''= sqrt (a<sup>2</sup>+b<sup>2</sup>) (Pythagoras’ theorem)'''
−
| | '''Complex numbers, complex plane'''
+
|| '''Complex numbers, complex plane'''
  
 
In '''complex plane''', '''''z''''' is a '''vector'''.  
 
In '''complex plane''', '''''z''''' is a '''vector'''.  
Line 303: Line 303:
 
According to '''Pythagoras’ theorem''', '''''r''''' is equal to '''squareroot of''' '''''a''''' '''squared plus''' '''''b''''' '''squared'''.
 
According to '''Pythagoras’ theorem''', '''''r''''' is equal to '''squareroot of''' '''''a''''' '''squared plus''' '''''b''''' '''squared'''.
 
|-
 
|-
−
| | Show the '''GeoGebra''' window.
+
|| Show the '''GeoGebra''' window.
−
| | Let us go back to the '''GeoGebra interface''' we were working on.
+
|| Let us go back to the '''GeoGebra interface''' we were working on.
  
 
We will now use the '''input bar''' instead of '''CAS''' view.  
 
We will now use the '''input bar''' instead of '''CAS''' view.  
 
|-
 
|-
−
| | Click and close '''CAS''' view.  
+
|| Click and close '''CAS''' view.  
−
| | Click and close '''CAS''' view.  
+
|| Click and close '''CAS''' view.  
 
|-
 
|-
−
| | In '''Algebra''' view, uncheck '''g of x''' to hide it.  
+
|| In '''Algebra''' view, uncheck '''g of x''' to hide it.  
−
| | In '''Algebra''' view, uncheck '''g of x''' to hide it.  
+
|| In '''Algebra''' view, uncheck '''g of x''' to hide it.  
 
|-
 
|-
−
| | In '''input bar''', type the following line.  
+
|| In '''input bar''', type the following line.  
  
 
'''h(x):=x^3-4x^2+x+6''' >> press '''Enter'''.
 
'''h(x):=x^3-4x^2+x+6''' >> press '''Enter'''.
  
−
| | In '''input bar''', type the following line.  
+
|| In '''input bar''', type the following line.  
  
 
'''h x''' in parentheses '''colon equals x caret 3 minus 4 space x caret 2 plus x plus 6'''.
 
'''h x''' in parentheses '''colon equals x caret 3 minus 4 space x caret 2 plus x plus 6'''.
Line 324: Line 324:
 
Press '''Enter'''.
 
Press '''Enter'''.
 
|-
 
|-
−
| | Drag boundaries to see '''Algebra''' and '''Graphics''' view properly.  
+
|| Drag boundaries to see '''Algebra''' and '''Graphics''' view properly.  
  
 
Point to the '''equation h(x)''' appearing in '''Algebra''' view.
 
Point to the '''equation h(x)''' appearing in '''Algebra''' view.
−
| | Drag boundaries to see '''Algebra''' and '''Graphics''' views properly.  
+
|| Drag boundaries to see '''Algebra''' and '''Graphics''' views properly.  
  
 
Observe equation '''h of x''' in '''Algebra''' view.
 
Observe equation '''h of x''' in '''Algebra''' view.
Line 333: Line 333:
 
Function '''h of x''' is graphed in '''Graphics''' view.
 
Function '''h of x''' is graphed in '''Graphics''' view.
 
|-
 
|-
−
| | Under '''Move Graphics View''', click on '''Zoom Out''' tool.  
+
|| Under '''Move Graphics View''', click on '''Zoom Out''' tool.  
  
 
Click in '''Graphics''' view.  
 
Click in '''Graphics''' view.  
−
| | Under '''Move Graphics View''', click on '''Zoom Out''' tool.  
+
|| Under '''Move Graphics View''', click on '''Zoom Out''' tool.  
  
 
Click in '''Graphics''' view.  
 
Click in '''Graphics''' view.  
 
|-
 
|-
−
| | Click on '''Move Graphics View''' and move '''Graphics''' background to see the graph.  
+
|| Click on '''Move Graphics View''' and move '''Graphics''' background to see the graph.  
−
| | Click on '''Move Graphics View''' and move '''Graphics''' background to see the graph.  
+
|| Click on '''Move Graphics View''' and move '''Graphics''' background to see the graph.  
 
|-
 
|-
−
| | In '''input bar''', type '''Root(h)''' and press '''Enter'''.  
+
|| In '''input bar''', type '''Root(h)''' and press '''Enter'''.  
−
| | In '''input bar''', type '''Root h''' in parentheses and press '''Enter'''.  
+
|| In '''input bar''', type '''Root h''' in parentheses and press '''Enter'''.  
 
|-
 
|-
−
| | Point to '''co-ordinates''' of three '''roots''' ('''A, B''' and '''C''') in '''Algebra''' view.  
+
|| Point to '''co-ordinates''' of three '''roots''' ('''A, B''' and '''C''') in '''Algebra''' view.  
−
| | The '''co-ordinates''' of three '''roots''' ('''A, B''' and '''C''') appear in '''Algebra''' view.  
+
|| The '''co-ordinates''' of three '''roots''' ('''A, B''' and '''C''') appear in '''Algebra''' view.  
 
|-
 
|-
−
| | Point to three '''roots''' mapped on the '''curve h of x''' in '''Graphics''' view.  
+
|| Point to three '''roots''' mapped on the '''curve h of x''' in '''Graphics''' view.  
−
| | The three '''roots''' are also mapped as '''x intercepts''' of the '''curve h of x''' in '''Graphics''' view.  
+
|| The three '''roots''' are also mapped as '''x intercepts''' of the '''curve h of x''' in '''Graphics''' view.  
 
|-
 
|-
−
| | In '''input bar''', type '''Extremum h''' in parentheses and press '''Enter'''.  
+
|| In '''input bar''', type '''Extremum h''' in parentheses and press '''Enter'''.  
−
| | In '''input bar''', type '''Extremum h''' in parentheses and press '''Enter'''.  
+
|| In '''input bar''', type '''Extremum h''' in parentheses and press '''Enter'''.  
 
|-
 
|-
−
| | Point to '''co-ordinates''' of two '''extrema''' ('''D'''and '''E''') in '''Algebra''' view.  
+
|| Point to '''co-ordinates''' of two '''extrema''' ('''D'''and '''E''') in '''Algebra''' view.  
−
| | '''Co-ordinates''' of two '''extrema''' ('''D''' and '''E''') appear in '''Algebra''' view.  
+
|| '''Co-ordinates''' of two '''extrema''' ('''D''' and '''E''') appear in '''Algebra''' view.  
 
|-
 
|-
−
| | Point to two '''extrema''' mapped on the '''curve h of x''' in '''Graphics''' view.  
+
|| Point to two '''extrema''' mapped on the '''curve h of x''' in '''Graphics''' view.  
−
| | The two '''extrema''' are also mapped on '''curve h of x''' in '''Graphics''' view.  
+
|| The two '''extrema''' are also mapped on '''curve h of x''' in '''Graphics''' view.  
 
|-
 
|-
−
| | '''Slide Number 11'''
+
|| '''Slide Number 11'''
  
 
'''Point of inflection'''
 
'''Point of inflection'''
Line 367: Line 367:
 
'''Point of inflection''' ('''PoI''') on a curve is the point where '''curve''' changes direction.
 
'''Point of inflection''' ('''PoI''') on a curve is the point where '''curve''' changes direction.
  
−
*To find '''co-ordinates''' of '''PoI (x,y)''', we equate 2nd '''derivative''' of given '''function''' to 0
+
* To find '''co-ordinates''' of '''PoI (x,y)''', we equate 2nd '''derivative''' of given '''function''' to 0
  
−
*Solve to get '''x''' ('''x co-ordinate''' of '''PoI''')
+
* Solve to get '''x''' ('''x co-ordinate''' of '''PoI''')
  
−
*Substitute this '''x''' in original '''function''' to get '''y co-ordinate'''
+
* Substitute this '''x''' in original '''function''' to get '''y co-ordinate'''
−
| | '''Point of inflection'''
+
|| '''Point of inflection'''
 
   
 
   
 
A '''point of inflection PoI''' on a curve is the point where the '''curve''' changes its direction.
 
A '''point of inflection PoI''' on a curve is the point where the '''curve''' changes its direction.
Line 386: Line 386:
 
Substitute this '''x''' in original '''function''' to get '''y co-ordinate'''.
 
Substitute this '''x''' in original '''function''' to get '''y co-ordinate'''.
 
|-
 
|-
−
| | Let us find the '''point of inflection''' on '''h(x)'''.  
+
|| Let us find the '''point of inflection''' on '''h(x)'''.  
−
| | Let us find the '''point of inflection''' on '''h of x'''.  
+
|| Let us find the '''point of inflection''' on '''h of x'''.  
 
|-
 
|-
−
| | In '''input bar''', type '''Inf''' >> choose '''InflectionPoint ( <Polynomial> )''' option from '''menu'''.
+
|| In '''input bar''', type '''Inf''' >> choose '''InflectionPoint ( <Polynomial> )''' option from '''menu'''.
−
| | In '''input bar''', type '''Inf''' and scroll down menu to choose '''InflectionPoint Polynomial''' option.
+
|| In '''input bar''', type '''Inf''' and scroll down menu to choose '''InflectionPoint Polynomial''' option.
 
|-
 
|-
−
| | Instead of highlighted '''Polynomial''', type '''h''' >> Press '''Enter'''.  
+
|| Instead of highlighted '''Polynomial''', type '''h''' >> Press '''Enter'''.  
−
| | Instead of highlighted '''Polynomial''', type '''h''' and press '''Enter'''.  
+
|| Instead of highlighted '''Polynomial''', type '''h''' and press '''Enter'''.  
 
|-
 
|-
−
| | Point to the '''point of inflection''' in '''Algebra''' view.  
+
|| Point to the '''point of inflection''' in '''Algebra''' view.  
−
| | In '''Algebra''' view, '''point of inflection''' appears as point '''F''', below the two '''extrema'''.  
+
|| In '''Algebra''' view, '''point of inflection''' appears as point '''F''', below the two '''extrema'''.  
 
|-
 
|-
−
| | Point to '''F''' on '''h(x)''' in '''Graphics''' view.  
+
|| Point to '''F''' on '''h(x)''' in '''Graphics''' view.  
−
| | '''F''' is mapped on '''h of x''' in '''Graphics''' view.  
+
|| '''F''' is mapped on '''h of x''' in '''Graphics''' view.  
 
|-
 
|-
−
| |  
+
||  
−
| | Correlate the '''degree''' of the '''polynomials''' and the number of '''roots''' seen so far.  
+
|| Correlate the '''degree''' of the '''polynomials''' and the number of '''roots''' seen so far.  
 
|-
 
|-
−
| | Point to '''CAS''', then '''Algebra''' and '''Graphics''' views.  
+
|| Point to '''CAS''', then '''Algebra''' and '''Graphics''' views.  
−
| | Observe that '''functions''' entered in '''CAS''' appear in '''Algebra''' and '''Graphics''' views.  
+
|| Observe that '''functions''' entered in '''CAS''' appear in '''Algebra''' and '''Graphics''' views.  
 
|-
 
|-
−
| | Point to '''Algebra''' and '''Graphics''' views, then '''CAS''' view.  
+
|| Point to '''Algebra''' and '''Graphics''' views, then '''CAS''' view.  
−
| | '''Functions''' entered in '''input bar''' appear in '''Algebra''' and '''Graphics''' views but not in '''CAS''' view.  
+
|| '''Functions''' entered in '''input bar''' appear in '''Algebra''' and '''Graphics''' views but not in '''CAS''' view.  
 
|-
 
|-
−
| |  
+
||  
−
| | Let us summarize.
+
|| Let us summarize.
 
|-
 
|-
−
| | '''Slide Number 12'''
+
|| '''Slide Number 12'''
  
 
'''Summary'''
 
'''Summary'''
−
| | In this tutorial, we have learnt to:
+
|| In this tutorial, we have learnt to:
  
−
*Plot graphs of '''polynomial functions''' using '''CAS''' view and '''input bar'''
+
* Plot graphs of '''polynomial functions''' using '''CAS''' view and '''input bar'''
  
−
*Find '''real roots, extrema''' and '''inflection point(s)'''
+
* Find '''real roots, extrema''' and '''inflection point(s)'''
  
−
*'''Complex roots''' will be covered in another tutorial
+
* '''Complex roots''' will be covered in another tutorial
 
|-
 
|-
−
| | '''Slide Number 13'''
+
|| '''Slide Number 13'''
 +
 
 
'''Assignment'''
 
'''Assignment'''
  
−
*d(x)=x<sup>2</sup>-6x+5
+
* d(x)=x<sup>2</sup>-6x+5
  
−
*e(x)=3x<sup>3</sup>-2x<sup>2</sup>+0.2x-1
+
* e(x)=3x<sup>3</sup>-2x<sup>2</sup>+0.2x-1
  
−
*f(x)=-2x<sup>4</sup>-x<sup>3</sup>+3x<sup>2</sup>
+
* f(x)=-2x<sup>4</sup>-x<sup>3</sup>+3x<sup>2</sup>
  
−
*g(x)=x<sup>5</sup>-7x<sup>4</sup>+9x<sup>3</sup>+23x<sup>2</sup>-50x+24
+
* g(x)=x<sup>5</sup>-7x<sup>4</sup>+9x<sup>3</sup>+23x<sup>2</sup>-50x+24
  
−
*h(x)=(4x+3)/(x-1)
+
* h(x)=(4x+3)/(x-1)
  
−
*i(x)=(3x<sup>2</sup>-2x-1)/(2x<sup>2</sup>+3x-2)
+
* i(x)=(3x<sup>2</sup>-2x-1)/(2x<sup>2</sup>+3x-2)
−
| | Assignment:
+
|| Assignment:
 
Plot '''graphs''' and find '''roots''', '''extrema''' and '''inflection points''' for the following '''polynomials'''.
 
Plot '''graphs''' and find '''roots''', '''extrema''' and '''inflection points''' for the following '''polynomials'''.
 
|-
 
|-
−
| | '''Slide Number 14'''
+
|| '''Slide Number 14'''
 +
 
 
'''About Spoken Tutorial project'''
 
'''About Spoken Tutorial project'''
−
| | The video at the following link summarizes the '''Spoken Tutorial''' project.
+
|| The video at the following link summarizes the '''Spoken Tutorial''' project.
  
 
Please download and watch it.
 
Please download and watch it.
 
|-
 
|-
−
| | '''Slide Number 15'''
+
|| '''Slide Number 15'''
 +
 
 
'''Spoken Tutorial workshops'''
 
'''Spoken Tutorial workshops'''
−
| | The '''Spoken Tutorial Project''' team conducts workshops and gives certificates.
+
|| The '''Spoken Tutorial Project''' team conducts workshops and gives certificates.
  
 
For more details, please write to us.
 
For more details, please write to us.
 
|-
 
|-
−
| | '''Slide Number 16'''
+
|| '''Slide Number 16'''
 +
 
 
'''Forum for specific questions:'''
 
'''Forum for specific questions:'''
 
Do you have questions in THIS Spoken Tutorial?
 
Do you have questions in THIS Spoken Tutorial?
 +
 
Please visit this site.
 
Please visit this site.
 +
 
Choose the '''minute''' and '''second''' where you have the question.
 
Choose the '''minute''' and '''second''' where you have the question.
 +
 
Explain your question briefly.
 
Explain your question briefly.
 +
 
Someone from our team will answer them.
 
Someone from our team will answer them.
−
| | Please post your timed queries on this forum.
+
|| Please post your timed queries on this forum.
 
|-
 
|-
−
| | '''Slide Number 17'''
+
|| '''Slide Number 17'''
 +
 
 
'''Acknowledgement'''
 
'''Acknowledgement'''
−
| | '''Spoken Tutorial Project''' is funded by '''NMEICT, MHRD''', Government of India.
+
|| '''Spoken Tutorial Project''' is funded by '''NMEICT, MHRD''', Government of India.
  
 
More information on this mission is available at this link.
 
More information on this mission is available at this link.
 
|-
 
|-
−
| |  
+
||  
−
| | This is '''Vidhya Iyer''' from '''IIT Bombay,''' signing off.
+
|| This is '''Vidhya Iyer''' from '''IIT Bombay,''' signing off.
  
 
Thank you for joining.
 
Thank you for joining.
 
|-
 
|-
 
|}
 
|}

Revision as of 16:08, 28 June 2018

Visual Cue Narration
Slide Number 1

Title Slide

Welcome to this tutorial on Roots of Polynomials.
Slide Number 2

Learning Objectives

In this tutorial, we will learn:
  • To plot graphs of polynomial equations
  • About complex numbers, real and imaginary roots
  • To find extrema and inflection points
Slide Number 3

Pre-requisites

www.spoken-tutorial.org

To follow this tutorial, you should be familiar with
  • GeoGebra interface
  • Basics of coordinate system
  • Polynomials
  • If not, for relevant tutorials, please visit our website.
Slide Number 4

System Requirement

Here I am using:
  • Ubuntu Linux OS version 14.04
  • GeoGebra 5.0.388.0-d
Let us begin with the binomial theorem.
Slide Number 5

Binomial Theorem

Binomial theorem states that if a, b Єℝ, index n is a positive integer,

  • 0 ≤ r ≤n, then
  • (a + b)n = nC0 an + nC1 an-1 b1 + nC2 an-2 b2 + … + nCr an-r br + … + nCn bn

Reminder: nC1 = n!/[1! (n-1)!]

a and b are real numbers.

index n is a positive integer.

r lies between 0 and n.

Binomial theorem states that a plus b raised to n can be expanded as shown.

Slide Number 6

Quadratic Equations and Roots

  • A second degree polynomial, y = a x2+ b x+ c has roots
  • x=- b ± sqrt{( b 2-4 ac)/2a }
  • where ▲= b2-4ac
  • When ▲< 0, roots are complex
  • When ▲=0, roots are real and equal
  • When ▲>0, roots are real and unequal
Quadratic Equations and Roots

A 2nd degree polynomial, y equals a x squared plus b x plus c has roots given by values of x.

x is equal to ratio of minus b plus or minus squareroot of b squared minus 4 a c to 2 a.

Where discriminant Delta is equal to b squared minus 4 a c

When Delta is less than 0, roots are complex

When Delta is equal to 0, roots are real and equal

When Delta is greater than 0, roots are real and unequal

Slide Number 7

Quadratic Equations and Roots

  • When roots are real, ax2+b x+ c =0 has extremum (xv, yv)
  • xv = - b/2a and yv= a xv2+ b xv+ c
Quadratic Equations and Roots

When roots are real, ax squared plus b x plus c equals 0 has extremum xv comma yv

xv equals minus b divided by 2 a and yv equals axv squared plus bxv plus c

Show the GeoGebra window. I have already opened the GeoGebra interface.
Click on View >> select CAS. Click on View tool and select CAS to open the CAS view.
In line 1 in CAS view, type f(x):=x^2-2x-3 >> press Enter. In line 1 in CAS view, type the following line.

f x in parentheses colon equals x caret 2 minus 2 space x minus 3.

To type caret symbol, hold Shift key down and press 6.

The space indicates multiplication.

Press Enter.

Drag boundary to see Algebra view properly. Drag boundary to see Algebra view properly.
Point to the equation f(x) appearing in Algebra view.

Point to exponent 2 in f(x).

Observe the equation f of x in Algebra view.

The degree of this quadratic polynomial f of x is 2.

Drag boundary to see Graphics view properly. Drag boundary to see Graphics view properly.
Click in Graphics view to see Graphics View toolbar. Click in Graphics view to see Graphics View toolbar.
Move Graphics View>> click on Zoom Out Under Move Graphics View, click on Zoom Out tool.
Click in Graphics view >> minimum vertex of parabola f. Click in Graphics view to see the minimum vertex of parabola f.
Click on Move Graphics View tool >> click in Graphics background. Click on Move Graphics View tool and click in Graphics background.
Hand symbol appears >> drag Graphics view to see parabola f. When hand symbol appears, drag Graphics view so you can see parabola f.
Drag boundaries Drag boundaries to see CAS view properly.
Type Root(f) in line 2 of CAS view >> press Enter. In line 2 of CAS view, type Root f in parentheses.

Press Enter.

Point to roots in CAS view. The roots appear below, in the same box, in curly brackets.
Point to roots in Graphics view. Note that these are the x-intercepts of parabola f in Graphics view.
Type Extremum(f) in line 3 of CAS view >> press Enter. In line 3 of CAS view, type Extremum f in parentheses.

Press Enter.

Point to extremum in CAS view. The extremum appears below, in the same box, in curly brackets.
Note that this is the minimum vertex of parabola f in Graphics view. Note that this is the minimum vertex of parabola f in Graphics view.
In line 4 in CAS view, type g(x):=x^2+5x+10 >> press Enter. In line 4 in CAS view, type the following line.

g x in parentheses colon equals x caret 2 plus 5 space x plus 10.

Press Enter.

Drag boundary to see Algebra view properly.

Point to the equation g(x) appearing in Algebra view.

Drag boundary to see Algebra view properly.

Observe the equation g of x in Algebra view.

Drag boundary to see Graphics view properly. Drag boundary to see Graphics view properly.
Uncheck f of x in CAS view.

Note that this also unchecks it in Algebra view and hides parabola f in Graphics view.

Uncheck f of x in CAS view.

Note that this also unchecks it in Algebra view and hides parabola f in Graphics view.

Click and drag Graphics view so you can see parabola g. Click in and drag Graphics view so you can see parabola g.
Again, drag boundary to see CAS view properly. Again, drag boundary to see CAS view properly.
Type Root(g) in line 5 of CAS view >> press Enter. In line 5 of CAS view, type Root g in parentheses.

Press Enter.

Point to empty curly brackets for roots in CAS view. Empty curly brackets appear below.

Parabola g does not have any real roots as it does not intersect x axis at all.

Roots are said to be complex.

Type Extremum(g) in line 6 of CAS view >> press Enter. In line 6 of CAS view, type Extremum g in parentheses.

Press Enter.

Point to extremum in CAS view. The extremum appears below, in the same box, in curly brackets.
Note that this is the minimum vertex of parabola g in Graphics view. Note that this is the minimum vertex of parabola g in Graphics view.
Point to Evaluate tool.

Point to extremum in form of fractions.

While Evaluate tool is highlighted in CAS View toolbar, the extremum appears as fractions.

Minus five divided by 2 comma 15 divided by 4.

Click on the extremum in line 6 and click on Numeric tool.

Point to extremum in form of decimals.

In line 6, click on the extremum and click on Numeric tool.

The extremum now appears in decimal form.

Minus 2 point 5 comma 3 point 7 5.

Let us look at complex numbers.
Slide Number 8

Complex numbers, XY plane


  • A complex number is expressed as z = a + bi: where 'a' = real part, ‘bi’ = imaginary part, and a and b are constants.
  • Imaginary number, i = sqrt{-1}


  • In the XY plane, a + bi is point (a, b).


  • In the complex plane, x axis = real axis, y axis = imaginary axis.
Complex numbers, XY plane

A complex number is expressed as z equals a plus bi.


a is the real part; bi is imaginary part;a and b are constants


i is imaginary number and is equal to square root of minus 1.


In the XY plane, a plus bi corresponds to the point a comma b.


In the complex plane, x axis is called real axis, y axis is called imaginary axis.

Slide Number 9

Complex numbers, complex plane

  • In complex plane, z is a vector with real axis coordinate a and imaginary axis coordinate b


  • Length of the vector z = |z| = r


  • r = sqrt (a2+b2) (Pythagoras’ theorem)
Complex numbers, complex plane

In complex plane, z is a vector.


Its real axis coordinate is a and imaginary axis coordinate is b.


The length of the vector z is equal to the absolute value of z and to r.


According to Pythagoras’ theorem, r is equal to squareroot of a squared plus b squared.

Show the GeoGebra window. Let us go back to the GeoGebra interface we were working on.

We will now use the input bar instead of CAS view.

Click and close CAS view. Click and close CAS view.
In Algebra view, uncheck g of x to hide it. In Algebra view, uncheck g of x to hide it.
In input bar, type the following line.

h(x):=x^3-4x^2+x+6 >> press Enter.

In input bar, type the following line.

h x in parentheses colon equals x caret 3 minus 4 space x caret 2 plus x plus 6.

Press Enter.

Drag boundaries to see Algebra and Graphics view properly.

Point to the equation h(x) appearing in Algebra view.

Drag boundaries to see Algebra and Graphics views properly.

Observe equation h of x in Algebra view.

Function h of x is graphed in Graphics view.

Under Move Graphics View, click on Zoom Out tool.

Click in Graphics view.

Under Move Graphics View, click on Zoom Out tool.

Click in Graphics view.

Click on Move Graphics View and move Graphics background to see the graph. Click on Move Graphics View and move Graphics background to see the graph.
In input bar, type Root(h) and press Enter. In input bar, type Root h in parentheses and press Enter.
Point to co-ordinates of three roots (A, B and C) in Algebra view. The co-ordinates of three roots (A, B and C) appear in Algebra view.
Point to three roots mapped on the curve h of x in Graphics view. The three roots are also mapped as x intercepts of the curve h of x in Graphics view.
In input bar, type Extremum h in parentheses and press Enter. In input bar, type Extremum h in parentheses and press Enter.
Point to co-ordinates of two extrema (Dand E) in Algebra view. Co-ordinates of two extrema (D and E) appear in Algebra view.
Point to two extrema mapped on the curve h of x in Graphics view. The two extrema are also mapped on curve h of x in Graphics view.
Slide Number 11

Point of inflection

Point of inflection (PoI) on a curve is the point where curve changes direction.

  • To find co-ordinates of PoI (x,y), we equate 2nd derivative of given function to 0
  • Solve to get x (x co-ordinate of PoI)
  • Substitute this x in original function to get y co-ordinate
Point of inflection

A point of inflection PoI on a curve is the point where the curve changes its direction.

To find the co-ordinates of PoI x comma y,

We equate second derivative of the given function to 0.


Solution of this equation gives us x (x co-ordinate of PoI).


Substitute this x in original function to get y co-ordinate.

Let us find the point of inflection on h(x). Let us find the point of inflection on h of x.
In input bar, type Inf >> choose InflectionPoint ( <Polynomial> ) option from menu. In input bar, type Inf and scroll down menu to choose InflectionPoint Polynomial option.
Instead of highlighted Polynomial, type h >> Press Enter. Instead of highlighted Polynomial, type h and press Enter.
Point to the point of inflection in Algebra view. In Algebra view, point of inflection appears as point F, below the two extrema.
Point to F on h(x) in Graphics view. F is mapped on h of x in Graphics view.
Correlate the degree of the polynomials and the number of roots seen so far.
Point to CAS, then Algebra and Graphics views. Observe that functions entered in CAS appear in Algebra and Graphics views.
Point to Algebra and Graphics views, then CAS view. Functions entered in input bar appear in Algebra and Graphics views but not in CAS view.
Let us summarize.
Slide Number 12

Summary

In this tutorial, we have learnt to:
  • Plot graphs of polynomial functions using CAS view and input bar
  • Find real roots, extrema and inflection point(s)
  • Complex roots will be covered in another tutorial
Slide Number 13

Assignment

  • d(x)=x2-6x+5
  • e(x)=3x3-2x2+0.2x-1
  • f(x)=-2x4-x3+3x2
  • g(x)=x5-7x4+9x3+23x2-50x+24
  • h(x)=(4x+3)/(x-1)
  • i(x)=(3x2-2x-1)/(2x2+3x-2)
Assignment:

Plot graphs and find roots, extrema and inflection points for the following polynomials.

Slide Number 14

About Spoken Tutorial project

The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

Slide Number 15

Spoken Tutorial workshops

The Spoken Tutorial Project team conducts workshops and gives certificates.

For more details, please write to us.

Slide Number 16

Forum for specific questions: Do you have questions in THIS Spoken Tutorial?

Please visit this site.

Choose the minute and second where you have the question.

Explain your question briefly.

Someone from our team will answer them.

Please post your timed queries on this forum.
Slide Number 17

Acknowledgement

Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

More information on this mission is available at this link.

This is Vidhya Iyer from IIT Bombay, signing off.

Thank you for joining.

Contributors and Content Editors

Madhurig, Nancyvarkey, Vidhya

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