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+ | {|border=1 | ||
+ | ||'''Time''' | ||
+ | ||'''Narration''' | ||
+ | |- | ||
+ | ||00:01 | ||
+ | ||Welcome to this tutorial on '''3D Geometry'''. | ||
+ | |||
+ | |- | ||
+ | ||00:05 | ||
+ | ||In this '''tutorial''', we will learn how to use '''GeoGebra''' to view: | ||
+ | |||
+ | And construct different structures in 3D space | ||
+ | |||
+ | |- | ||
+ | ||00:17 | ||
+ | ||Solids of rotation of polynomial functions | ||
+ | |||
+ | |- | ||
+ | ||00:21 | ||
+ | ||Trigonometric functions in 3D space | ||
+ | |- | ||
+ | ||00:25 | ||
+ | ||Here I am using: | ||
+ | |||
+ | '''Ubuntu Linux''' OS version 16.04 | ||
+ | |||
+ | |- | ||
+ | ||00:32 | ||
+ | ||'''GeoGebra''' 5.0.481.0 hyphen d | ||
+ | |- | ||
+ | ||00:39 | ||
+ | ||To follow this '''tutorial''', you should be familiar with: | ||
+ | |||
+ | |- | ||
+ | ||00:43 | ||
+ | ||'''GeoGebra''' interface | ||
+ | |||
+ | Geometry | ||
+ | |||
+ | |- | ||
+ | ||00:48 | ||
+ | ||For relevant '''tutorials''', please visit our website. | ||
+ | |||
+ | |- | ||
+ | ||00:53 | ||
+ | ||This image shows the '''rectangular coordinate system'''. | ||
+ | |||
+ | |- | ||
+ | ||00:58 | ||
+ | ||It is made up of mutually perpendicular axes and planes formed by them. | ||
+ | |||
+ | |- | ||
+ | ||01:04 | ||
+ | ||The axes are '''x''' (in red), '''y''' (in green) and '''z''' (in blue). | ||
+ | |||
+ | |- | ||
+ | ||01:11 | ||
+ | ||All points in 3D space are denoted by their x y z coordinates. | ||
+ | |||
+ | |- | ||
+ | ||01:18 | ||
+ | ||The point of intersection of the three axes is the '''origin O 0 comma 0 comma 0'''. | ||
+ | |||
+ | |- | ||
+ | ||01:27 | ||
+ | ||The gray rectangle in the image depicts the '''XY''' plane. | ||
+ | |||
+ | |- | ||
+ | ||01:33 | ||
+ | ||The planes divide space into 8 octants. | ||
+ | |||
+ | |- | ||
+ | ||01:38 | ||
+ | ||Point '''A''' is in the '''XOYZ''' octant and has the '''coordinates 4 comma 4 comma 2'''. | ||
+ | |- | ||
+ | ||01:48 | ||
+ | ||Let us draw a 3D pyramid in '''GeoGebra'''. | ||
+ | |||
+ | |- | ||
+ | ||01:53 | ||
+ | ||I have already opened a new window in '''GeoGebra'''. | ||
+ | |||
+ | |- | ||
+ | ||01:58 | ||
+ | ||This time, we work with '''Algebra, 2D Graphics''' and '''3D Graphics''' views. | ||
+ | |- | ||
+ | ||02:05 | ||
+ | ||Under '''View''', select '''3D Graphics'''. | ||
+ | |- | ||
+ | ||02:09 | ||
+ | ||Click in '''2D Graphics View''' to draw in '''2D'''. | ||
+ | |- | ||
+ | ||02:14 | ||
+ | ||Drag the boundary to see '''2D Graphics''' properly. | ||
+ | |- | ||
+ | ||02:19 | ||
+ | ||Click in '''2D Graphics'''. | ||
+ | |- | ||
+ | ||02:22 | ||
+ | ||In '''2D Graphics''' view, click on the '''Polygon''' tool and click on origin 0 comma 0. | ||
+ | |||
+ | |- | ||
+ | ||02:31 | ||
+ | ||This creates point '''A''' at the origin. | ||
+ | |- | ||
+ | ||02:35 | ||
+ | ||Then click on 2 comma 0 to create point '''B'''. | ||
+ | |- | ||
+ | ||02:40 | ||
+ | ||Click on 2 comma 2 for '''C''' and on 0 comma 2 to draw '''D'''. | ||
+ | |- | ||
+ | ||02:48 | ||
+ | ||Finally, click again on '''A'''. | ||
+ | |- | ||
+ | ||02:52 | ||
+ | ||Note that a quadrilateral '''q1''' is seen in '''2D''' and '''3D Graphics''' views. | ||
+ | |||
+ | |- | ||
+ | ||03:00 | ||
+ | ||The length of each side is 2 units. | ||
+ | |- | ||
+ | ||03:04 | ||
+ | ||Click on the '''Move''' tool. | ||
+ | |- | ||
+ | ||03:07 | ||
+ | ||Click in '''2D Graphics''' and drag the background. | ||
+ | |- | ||
+ | ||03:11 | ||
+ | ||Drag the boundary to see '''3D Graphics''' properly. | ||
+ | |- | ||
+ | ||03:16 | ||
+ | || Click in '''3D Graphics''' and under '''Pyramid''', on the '''Extrude to Pyramid or Cone''' tool. | ||
+ | |||
+ | |- | ||
+ | ||03:25 | ||
+ | ||In '''3D Graphics''' view, click on the square. | ||
+ | |- | ||
+ | ||03:29 | ||
+ | ||In the '''Altitude''' text-box that opens, type 3 and click '''OK'''. | ||
+ | |- | ||
+ | ||03:36 | ||
+ | ||A pyramid '''e''' appears in '''3D Graphics''' view. | ||
+ | |||
+ | |- | ||
+ | ||03:40 | ||
+ | ||Its base is the quadrilateral '''q1'''. | ||
+ | |||
+ | |- | ||
+ | ||03:44 | ||
+ | ||Its apex is '''E''' 1 comma 1 comma 3. | ||
+ | |||
+ | |- | ||
+ | ||03:49 | ||
+ | ||Its altitude or height is 3 units. | ||
+ | |- | ||
+ | ||03:54 | ||
+ | ||'''Rotation of a Polynomial''' | ||
+ | |||
+ | |- | ||
+ | ||03:57 | ||
+ | ||Let us rotate '''f of x''' equals minus '''2 x raised to 4''' minus '''x cubed''' plus '''3 x squared'''. | ||
+ | |||
+ | |- | ||
+ | ||04:07 | ||
+ | ||We will rotate the part that lies in the second quadrant, in '''XY''' plane, about the '''x-axis'''. | ||
+ | |- | ||
+ | ||04:16 | ||
+ | ||I have already opened a new window in '''GeoGebra'''. | ||
+ | |||
+ | |- | ||
+ | ||04:21 | ||
+ | ||We will initially work with '''Algebra''' and '''2D Graphics''' views and open '''3D Graphics''' view later. | ||
+ | |||
+ | |- | ||
+ | ||04:29 | ||
+ | ||In the '''input bar''', type the following line. | ||
+ | |||
+ | |- | ||
+ | ||04:33 | ||
+ | ||To type the '''caret symbol''', hold '''Shift''' key down and press 6. | ||
+ | |||
+ | |- | ||
+ | ||04:36 | ||
+ | ||Spaces here denote multiplication. | ||
+ | |||
+ | Press '''Enter'''. | ||
+ | |- | ||
+ | ||04:46 | ||
+ | ||Under '''Perpendicular Line''', click on '''Parallel line''' and on the '''y-axis'''. | ||
+ | |- | ||
+ | ||04:54 | ||
+ | ||Keep the '''cursor''' on the '''x-axis'''. | ||
+ | |- | ||
+ | ||04:58 | ||
+ | ||Drag it along until you see '''function f, x-axis''' at the intersection of '''f''' and '''x-axis'''. | ||
+ | |- | ||
+ | ||05:07 | ||
+ | ||Click on this intersection point. | ||
+ | |- | ||
+ | ||05:10 | ||
+ | ||Point '''A''' appears. | ||
+ | |- | ||
+ | ||05:13 | ||
+ | ||Click on '''Slider''' and in '''Graphics''' view. | ||
+ | |- | ||
+ | ||05:18 | ||
+ | ||A '''Slider''' dialog-box opens. | ||
+ | |- | ||
+ | ||05:21 | ||
+ | ||Leave '''a''' as the '''Name'''. | ||
+ | |- | ||
+ | ||05:24 | ||
+ | || Change '''Min''' value to '''minus''' 1.5, '''Max''' value to 0 and '''Increment''' to 0.05. | ||
+ | |- | ||
+ | ||05:34 | ||
+ | ||Click '''OK'''. | ||
+ | |- | ||
+ | ||05:36 | ||
+ | ||This creates '''slider a''', which changes the value of '''a''' from minus 1.5 to 0. | ||
+ | |||
+ | |- | ||
+ | ||05:45 | ||
+ | ||It will focus on the part of the graph in the second '''quadrant'''. | ||
+ | |||
+ | |- | ||
+ | ||05:51 | ||
+ | ||In the '''input bar''', type the following in parentheses. | ||
+ | |||
+ | |- | ||
+ | ||05:55 | ||
+ | ||'''a''' comma '''f a''' in parentheses. | ||
+ | |||
+ | Press '''Enter'''. | ||
+ | |- | ||
+ | ||06:02 | ||
+ | ||This creates point '''B''' whose '''x coordinate''' is the value of '''a'''. | ||
+ | |||
+ | |- | ||
+ | ||06:09 | ||
+ | ||Its '''y-coordinate''' lies along the curve described by the '''function f''' between '''x''' equals 1.5 and 0. | ||
+ | |- | ||
+ | ||06:19 | ||
+ | ||Right-click on '''slider a''' and check '''Animation On'''. | ||
+ | |- | ||
+ | ||06:25 | ||
+ | ||Point '''B''' travels along '''function f''' as '''a''' changes. | ||
+ | |- | ||
+ | ||06:31 | ||
+ | ||Right-click on '''slider a''' and uncheck '''Animation On'''. | ||
+ | |- | ||
+ | ||06:37 | ||
+ | ||In the '''input bar''', type '''a''' comma 0 in parentheses and press '''Enter'''. | ||
+ | |- | ||
+ | ||06:47 | ||
+ | ||This creates point '''C'''. | ||
+ | |||
+ | |- | ||
+ | ||06:50 | ||
+ | ||As its '''x co-ordinate a''' changes, '''C''' moves below point '''B''' along the '''x-axis'''. | ||
+ | |- | ||
+ | ||06:58 | ||
+ | ||Under '''Line''', click on '''Segment''' and click on '''B''' and '''C''' to join them. | ||
+ | |- | ||
+ | ||07:07 | ||
+ | ||Click on '''Move Graphics View''' and drag the background to the left. | ||
+ | |- | ||
+ | ||07:13 | ||
+ | ||Click on '''View''' and check '''3D Graphics''' to see the '''3D Graphics''' view. | ||
+ | |- | ||
+ | ||07:20 | ||
+ | ||Note that what is drawn in '''2D Graphics''' appears in the '''XY''' plane, in '''3D Graphics'''. | ||
+ | |- | ||
+ | ||07:27 | ||
+ | ||Click in '''3D Graphics''' view and on '''Rotate 3D Graphics View'''. | ||
+ | |||
+ | |- | ||
+ | ||07:34 | ||
+ | ||Rotate '''3D Graphics''' to see the curve properly. | ||
+ | |||
+ | |- | ||
+ | ||07:41 | ||
+ | ||Place the '''cursor''' on the '''y-axis''' in green. | ||
+ | |||
+ | |- | ||
+ | ||07:46 | ||
+ | ||Click to see an arrow aligned with the '''y-axis'''. | ||
+ | |||
+ | |- | ||
+ | ||07:51 | ||
+ | ||Drag to pull the '''y-axis''' in or outwards to see the curve. | ||
+ | |||
+ | |- | ||
+ | ||07:58 | ||
+ | ||In the '''input bar''', type the following line. | ||
+ | |||
+ | |- | ||
+ | ||08:02 | ||
+ | ||This creates circle '''c''' with center at point '''C'''. | ||
+ | |||
+ | |- | ||
+ | ||08:07 | ||
+ | ||Its radius is equal to '''f of a''' corresponding to the value of '''a''' on '''slider a'''. | ||
+ | |||
+ | |- | ||
+ | ||08:15 | ||
+ | ||Its rotation is around the '''x-axis'''. | ||
+ | |||
+ | Press '''Enter'''. | ||
+ | |- | ||
+ | ||08:21 | ||
+ | ||In '''Algebra''' view, right-click on circle '''c''' and check '''Trace On''' option. | ||
+ | |- | ||
+ | ||08:28 | ||
+ | ||Right click on '''slider a''' and select '''Animation On''' option. | ||
+ | |- | ||
+ | ||08:35 | ||
+ | ||Observe the solid traced as '''a''' changes. | ||
+ | |- | ||
+ | ||08:39 | ||
+ | ||Watch both '''2D''' and '''3D Graphics''' views. | ||
+ | |- | ||
+ | ||08:44 | ||
+ | ||Segment '''BC''' moves between the '''x-axis''' and '''function f'''. | ||
+ | |- | ||
+ | ||08:50 | ||
+ | ||The part of '''function f''' that is in the second '''quadrant''' in 2D, rotates around the '''x-axis'''. | ||
+ | |- | ||
+ | ||08:58 | ||
+ | ||Drag '''3D Graphics''' to see it from another angle. | ||
+ | |- | ||
+ | ||09:03 | ||
+ | ||Finally, let us look at '''trigonometric functions''' in 3D. | ||
+ | |||
+ | |- | ||
+ | ||09:09 | ||
+ | ||I have already opened a new window in '''GeoGebra'''. | ||
+ | |- | ||
+ | ||09:14 | ||
+ | ||Under '''View''', click on '''3D Graphics'''. | ||
+ | |- | ||
+ | ||09:19 | ||
+ | ||Drag the boundary to see '''2D Graphics''' properly. | ||
+ | |- | ||
+ | ||09:23 | ||
+ | ||Click in '''2D Graphics''', then on the '''Slider''' tool and in '''Graphics''' view. | ||
+ | |- | ||
+ | ||09:32 | ||
+ | ||A '''slider''' dialog-box opens. | ||
+ | |||
+ | |- | ||
+ | ||09:35 | ||
+ | ||By default, the '''Number''' radio-button is selected. | ||
+ | |||
+ | In the '''Name''' field, type '''t'''. | ||
+ | |- | ||
+ | ||09:43 | ||
+ | ||Set '''Min''' to minus 6, '''Max''' to 16 and '''increment''' of 0.1. | ||
+ | |||
+ | Click '''OK'''. | ||
+ | |- | ||
+ | ||09:54 | ||
+ | ||This creates a '''slider t''' which will change '''t''' from minus 6 to 16. | ||
+ | |- | ||
+ | ||10:01 | ||
+ | ||In the '''input bar''', type '''f t''' in parentheses equals '''cos t''' in parentheses and press '''Enter'''. | ||
+ | |- | ||
+ | ||10:12 | ||
+ | ||Click in '''2D Graphics'''. | ||
+ | |- | ||
+ | ||10:15 | ||
+ | ||Under '''Move Graphics View''', click on '''Zoom Out''' and click in '''2D Graphics'''. | ||
+ | |- | ||
+ | ||10:23 | ||
+ | ||Click on '''Move Graphics View''' and drag the background. | ||
+ | |- | ||
+ | ||10:28 | ||
+ | ||You can see the graph of the '''cosine function''' of '''f of t''', in '''2D''' and '''3D Graphics''' views. | ||
+ | |- | ||
+ | ||10:37 | ||
+ | ||Similarly, in the '''input bar''', type '''g t''' in parentheses equals '''sin t''' in parentheses. | ||
+ | |||
+ | Press '''Enter'''. | ||
+ | |- | ||
+ | ||10:49 | ||
+ | ||'''Sine function''' graph of '''g of t''' appears. | ||
+ | |- | ||
+ | ||10:53 | ||
+ | ||In the '''input bar''', type '''h t''' in parentheses equals '''t''' divided by 4 and press '''Enter'''. | ||
+ | |- | ||
+ | ||11:05 | ||
+ | ||Line '''h of t''' is of the form '''y''' equals '''mx''' where slope '''m''' is 1 divided by 4. | ||
+ | |- | ||
+ | ||11:14 | ||
+ | ||Click in '''3D Graphics''' view. | ||
+ | |- | ||
+ | ||11:17 | ||
+ | ||Click on the '''Point''' tool and click in the gray area in '''3D Graphics''' view. | ||
+ | |||
+ | This creates point '''A'''. | ||
+ | |- | ||
+ | ||11:26 | ||
+ | ||Drag the boundary to see its '''co-ordinates''' properly. | ||
+ | |- | ||
+ | ||11:30 | ||
+ | ||In '''Algebra''' view, double-click on '''A'''. | ||
+ | |||
+ | |- | ||
+ | ||11:34 | ||
+ | ||Change the '''coordinates''' to the following. Press '''Enter'''. | ||
+ | |- | ||
+ | ||11:39 | ||
+ | ||The '''x- coordinate''' of '''A''' is '''cos t'''. | ||
+ | |||
+ | |- | ||
+ | ||11:44 | ||
+ | ||The '''y-coordinate''' is '''sin t''' and '''t''' divided by '''4''' is its '''z coordinate'''. | ||
+ | |- | ||
+ | ||11:53 | ||
+ | ||Right-click on '''slider t''' and click on '''Object Properties'''. | ||
+ | |- | ||
+ | ||11:58 | ||
+ | || A '''Preferences''' dialog-box opens. | ||
+ | |||
+ | |- | ||
+ | ||12:02 | ||
+ | ||Click on '''Slider''' tab. | ||
+ | |||
+ | |- | ||
+ | ||12:05 | ||
+ | ||Under '''Animation''', for '''Repeat''', choose option “'''Increasing'''” from the dropdown menu. | ||
+ | |- | ||
+ | ||12:12 | ||
+ | ||Close the '''Preferences''' dialog box. | ||
+ | |- | ||
+ | ||12:15 | ||
+ | ||In '''Algebra''' view, right-click on '''A''' and select '''Trace On'''. | ||
+ | |- | ||
+ | ||12:22 | ||
+ | ||Right-click on '''slider t''' and check '''Animation On'''. | ||
+ | |- | ||
+ | ||12:27 | ||
+ | ||Point '''A''' traces a '''helix''' in '''3D''' space with '''coordinates''' mentioned earlier. | ||
+ | |- | ||
+ | ||12:34 | ||
+ | ||Click in '''Rotate 3D Graphic View''' and rotate the background. | ||
+ | |||
+ | |- | ||
+ | ||12:39 | ||
+ | ||Rotate '''3D Graphics''' view so you are looking down the '''z-axis''' at the '''XY''' plane. | ||
+ | |- | ||
+ | ||12:46 | ||
+ | ||Note that the traces of '''A''' are the circumference of a '''unit circle'''. | ||
+ | |||
+ | |- | ||
+ | ||12:52 | ||
+ | ||Point '''A''' moves along the circle as angle '''t''' changes. | ||
+ | |||
+ | |- | ||
+ | ||12:58 | ||
+ | ||In '''2D''', its '''coordinates''' are '''cos t''' comma '''sin t'''. | ||
+ | |- | ||
+ | ||13:05 | ||
+ | ||Let us summarize. | ||
+ | |- | ||
+ | ||13:07 | ||
+ | ||In this '''tutorial''', we have learnt how to use '''GeoGebra''' to view: | ||
+ | |||
+ | |- | ||
+ | ||13:13 | ||
+ | ||And construct different structures in 3D space | ||
+ | |||
+ | |- | ||
+ | ||13:17 | ||
+ | ||Solids of rotation of polynomial functions | ||
+ | |||
+ | |- | ||
+ | ||13:21 | ||
+ | ||Trigonometric functions in 3D space | ||
+ | |- | ||
+ | ||13:25 | ||
+ | ||As an assignment: | ||
+ | |||
+ | Construct a prism and a cylinder anywhere in 3D space. | ||
+ | |||
+ | |- | ||
+ | ||13:33 | ||
+ | ||Draw lines to pierce the structures and find their intersection points. | ||
+ | |||
+ | |- | ||
+ | ||13:39 | ||
+ | ||Graph the given '''polynomial'''. | ||
+ | |||
+ | |- | ||
+ | ||13:42 | ||
+ | ||Show the solid formed due to rotation of the peak, in the first '''quadrant''', in the '''XY''' plane. | ||
+ | |- | ||
+ | ||13:50 | ||
+ | || As another assignment, | ||
+ | |||
+ | You tried to fly a kite off a cliff. The kite got dumped into the lake below. | ||
+ | |||
+ | |- | ||
+ | ||13:59 | ||
+ | ||You gave out 325 feet of string. | ||
+ | |||
+ | |- | ||
+ | ||14:03 | ||
+ | ||The angle of declination from where you stand at the cliff’s edge to the kite is 15 degrees. | ||
+ | |||
+ | How high is the cliff? | ||
+ | |- | ||
+ | ||14:13 | ||
+ | ||The video at the following link summarizes the '''Spoken Tutorial''' project. | ||
+ | |||
+ | Please download and watch it. | ||
+ | |- | ||
+ | ||14:21 | ||
+ | ||The '''Spoken Tutorial '''project''' '''team: conducts workshops using spoken tutorials and | ||
+ | |||
+ | gives certificates on passing online tests. | ||
+ | |||
+ | |- | ||
+ | ||14:31 | ||
+ | ||For more details, please write to us. | ||
+ | |- | ||
+ | ||14:34 | ||
+ | ||Please post your timed queries on this forum. | ||
+ | |- | ||
+ | ||14:38 | ||
+ | ||'''Spoken Tutorial''' project is funded by NMEICT, MHRD, Government of India. | ||
+ | |||
+ | More information on this mission is available at this link. | ||
+ | |- | ||
+ | ||14:51 | ||
+ | ||This is '''Vidhya Iyer''' from '''IIT Bombay,''' signing off. | ||
+ | |||
+ | Thank you for joining. | ||
+ | |- | ||
+ | |} |
Latest revision as of 12:38, 21 October 2020
Time | Narration |
00:01 | Welcome to this tutorial on 3D Geometry. |
00:05 | In this tutorial, we will learn how to use GeoGebra to view:
And construct different structures in 3D space |
00:17 | Solids of rotation of polynomial functions |
00:21 | Trigonometric functions in 3D space |
00:25 | Here I am using:
Ubuntu Linux OS version 16.04 |
00:32 | GeoGebra 5.0.481.0 hyphen d |
00:39 | To follow this tutorial, you should be familiar with: |
00:43 | GeoGebra interface
Geometry |
00:48 | For relevant tutorials, please visit our website. |
00:53 | This image shows the rectangular coordinate system. |
00:58 | It is made up of mutually perpendicular axes and planes formed by them. |
01:04 | The axes are x (in red), y (in green) and z (in blue). |
01:11 | All points in 3D space are denoted by their x y z coordinates. |
01:18 | The point of intersection of the three axes is the origin O 0 comma 0 comma 0. |
01:27 | The gray rectangle in the image depicts the XY plane. |
01:33 | The planes divide space into 8 octants. |
01:38 | Point A is in the XOYZ octant and has the coordinates 4 comma 4 comma 2. |
01:48 | Let us draw a 3D pyramid in GeoGebra. |
01:53 | I have already opened a new window in GeoGebra. |
01:58 | This time, we work with Algebra, 2D Graphics and 3D Graphics views. |
02:05 | Under View, select 3D Graphics. |
02:09 | Click in 2D Graphics View to draw in 2D. |
02:14 | Drag the boundary to see 2D Graphics properly. |
02:19 | Click in 2D Graphics. |
02:22 | In 2D Graphics view, click on the Polygon tool and click on origin 0 comma 0. |
02:31 | This creates point A at the origin. |
02:35 | Then click on 2 comma 0 to create point B. |
02:40 | Click on 2 comma 2 for C and on 0 comma 2 to draw D. |
02:48 | Finally, click again on A. |
02:52 | Note that a quadrilateral q1 is seen in 2D and 3D Graphics views. |
03:00 | The length of each side is 2 units. |
03:04 | Click on the Move tool. |
03:07 | Click in 2D Graphics and drag the background. |
03:11 | Drag the boundary to see 3D Graphics properly. |
03:16 | Click in 3D Graphics and under Pyramid, on the Extrude to Pyramid or Cone tool. |
03:25 | In 3D Graphics view, click on the square. |
03:29 | In the Altitude text-box that opens, type 3 and click OK. |
03:36 | A pyramid e appears in 3D Graphics view. |
03:40 | Its base is the quadrilateral q1. |
03:44 | Its apex is E 1 comma 1 comma 3. |
03:49 | Its altitude or height is 3 units. |
03:54 | Rotation of a Polynomial |
03:57 | Let us rotate f of x equals minus 2 x raised to 4 minus x cubed plus 3 x squared. |
04:07 | We will rotate the part that lies in the second quadrant, in XY plane, about the x-axis. |
04:16 | I have already opened a new window in GeoGebra. |
04:21 | We will initially work with Algebra and 2D Graphics views and open 3D Graphics view later. |
04:29 | In the input bar, type the following line. |
04:33 | To type the caret symbol, hold Shift key down and press 6. |
04:36 | Spaces here denote multiplication.
Press Enter. |
04:46 | Under Perpendicular Line, click on Parallel line and on the y-axis. |
04:54 | Keep the cursor on the x-axis. |
04:58 | Drag it along until you see function f, x-axis at the intersection of f and x-axis. |
05:07 | Click on this intersection point. |
05:10 | Point A appears. |
05:13 | Click on Slider and in Graphics view. |
05:18 | A Slider dialog-box opens. |
05:21 | Leave a as the Name. |
05:24 | Change Min value to minus 1.5, Max value to 0 and Increment to 0.05. |
05:34 | Click OK. |
05:36 | This creates slider a, which changes the value of a from minus 1.5 to 0. |
05:45 | It will focus on the part of the graph in the second quadrant. |
05:51 | In the input bar, type the following in parentheses. |
05:55 | a comma f a in parentheses.
Press Enter. |
06:02 | This creates point B whose x coordinate is the value of a. |
06:09 | Its y-coordinate lies along the curve described by the function f between x equals 1.5 and 0. |
06:19 | Right-click on slider a and check Animation On. |
06:25 | Point B travels along function f as a changes. |
06:31 | Right-click on slider a and uncheck Animation On. |
06:37 | In the input bar, type a comma 0 in parentheses and press Enter. |
06:47 | This creates point C. |
06:50 | As its x co-ordinate a changes, C moves below point B along the x-axis. |
06:58 | Under Line, click on Segment and click on B and C to join them. |
07:07 | Click on Move Graphics View and drag the background to the left. |
07:13 | Click on View and check 3D Graphics to see the 3D Graphics view. |
07:20 | Note that what is drawn in 2D Graphics appears in the XY plane, in 3D Graphics. |
07:27 | Click in 3D Graphics view and on Rotate 3D Graphics View. |
07:34 | Rotate 3D Graphics to see the curve properly. |
07:41 | Place the cursor on the y-axis in green. |
07:46 | Click to see an arrow aligned with the y-axis. |
07:51 | Drag to pull the y-axis in or outwards to see the curve. |
07:58 | In the input bar, type the following line. |
08:02 | This creates circle c with center at point C. |
08:07 | Its radius is equal to f of a corresponding to the value of a on slider a. |
08:15 | Its rotation is around the x-axis.
Press Enter. |
08:21 | In Algebra view, right-click on circle c and check Trace On option. |
08:28 | Right click on slider a and select Animation On option. |
08:35 | Observe the solid traced as a changes. |
08:39 | Watch both 2D and 3D Graphics views. |
08:44 | Segment BC moves between the x-axis and function f. |
08:50 | The part of function f that is in the second quadrant in 2D, rotates around the x-axis. |
08:58 | Drag 3D Graphics to see it from another angle. |
09:03 | Finally, let us look at trigonometric functions in 3D. |
09:09 | I have already opened a new window in GeoGebra. |
09:14 | Under View, click on 3D Graphics. |
09:19 | Drag the boundary to see 2D Graphics properly. |
09:23 | Click in 2D Graphics, then on the Slider tool and in Graphics view. |
09:32 | A slider dialog-box opens. |
09:35 | By default, the Number radio-button is selected.
In the Name field, type t. |
09:43 | Set Min to minus 6, Max to 16 and increment of 0.1.
Click OK. |
09:54 | This creates a slider t which will change t from minus 6 to 16. |
10:01 | In the input bar, type f t in parentheses equals cos t in parentheses and press Enter. |
10:12 | Click in 2D Graphics. |
10:15 | Under Move Graphics View, click on Zoom Out and click in 2D Graphics. |
10:23 | Click on Move Graphics View and drag the background. |
10:28 | You can see the graph of the cosine function of f of t, in 2D and 3D Graphics views. |
10:37 | Similarly, in the input bar, type g t in parentheses equals sin t in parentheses.
Press Enter. |
10:49 | Sine function graph of g of t appears. |
10:53 | In the input bar, type h t in parentheses equals t divided by 4 and press Enter. |
11:05 | Line h of t is of the form y equals mx where slope m is 1 divided by 4. |
11:14 | Click in 3D Graphics view. |
11:17 | Click on the Point tool and click in the gray area in 3D Graphics view.
This creates point A. |
11:26 | Drag the boundary to see its co-ordinates properly. |
11:30 | In Algebra view, double-click on A. |
11:34 | Change the coordinates to the following. Press Enter. |
11:39 | The x- coordinate of A is cos t. |
11:44 | The y-coordinate is sin t and t divided by 4 is its z coordinate. |
11:53 | Right-click on slider t and click on Object Properties. |
11:58 | A Preferences dialog-box opens. |
12:02 | Click on Slider tab. |
12:05 | Under Animation, for Repeat, choose option “Increasing” from the dropdown menu. |
12:12 | Close the Preferences dialog box. |
12:15 | In Algebra view, right-click on A and select Trace On. |
12:22 | Right-click on slider t and check Animation On. |
12:27 | Point A traces a helix in 3D space with coordinates mentioned earlier. |
12:34 | Click in Rotate 3D Graphic View and rotate the background. |
12:39 | Rotate 3D Graphics view so you are looking down the z-axis at the XY plane. |
12:46 | Note that the traces of A are the circumference of a unit circle. |
12:52 | Point A moves along the circle as angle t changes. |
12:58 | In 2D, its coordinates are cos t comma sin t. |
13:05 | Let us summarize. |
13:07 | In this tutorial, we have learnt how to use GeoGebra to view: |
13:13 | And construct different structures in 3D space |
13:17 | Solids of rotation of polynomial functions |
13:21 | Trigonometric functions in 3D space |
13:25 | As an assignment:
Construct a prism and a cylinder anywhere in 3D space. |
13:33 | Draw lines to pierce the structures and find their intersection points. |
13:39 | Graph the given polynomial. |
13:42 | Show the solid formed due to rotation of the peak, in the first quadrant, in the XY plane. |
13:50 | As another assignment,
You tried to fly a kite off a cliff. The kite got dumped into the lake below. |
13:59 | You gave out 325 feet of string. |
14:03 | The angle of declination from where you stand at the cliff’s edge to the kite is 15 degrees.
How high is the cliff? |
14:13 | The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
14:21 | The Spoken Tutorial project team: conducts workshops using spoken tutorials and
gives certificates on passing online tests. |
14:31 | For more details, please write to us. |
14:34 | Please post your timed queries on this forum. |
14:38 | Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.
More information on this mission is available at this link. |
14:51 | This is Vidhya Iyer from IIT Bombay, signing off.
Thank you for joining. |