FUNCTIONS AND GRAPHS VIII
Activities with straight lines
Finding the equation of a given straight line.
In the following exercise you will find a way to determine the equation of a straight line.
You should bear in mind the following rules:
- You can only make one guess for each straight line, because on doing so, the orange line changes place, although on moving it leaves a shadow which is useful to check whether you have guessed correctly.
- If you are completely right the shadow will not be seen, because it is covered up by the the line you have written.
- You can erase the previous shadows by clicking on the applet with the secondary mouse button, but your lines will also be deleted.
1.- Investigate the equation of the orange straight line and make a guess: write it on the blue equation text field and press the [Return] key. You should get six consecutive correct answers. However, read the following advice first:
- To calculate the slope use the help of the green and blue segments. (You can write decimal numbers and also fractions, for example: y=3/5*x + 2)
- After, watch where the line intersects the ordinate axis.
Finding the equation of any straight line
This exercise is similar to the previous one, and the same rules are used.
2.- Investigate the equation of the straight orange line and make a guess. You can move the yellow point to obtain the difference of co-ordinates of two points on the straight line. You should get six consecutive correct answers.
Finding a staight line knowing its slope and a point through which it passes.
The object is to of finding the equation of a straight line that passes through an indicated point, if its gradient is known.
3.- Express the equation using the point and the slope. (You can write decimal numbers and also fractions, for example: y - 2 = 3/5 * (x+1)).
You should get 6 consecutive correct answers.
Finding the straight line that passes through two points.
The object is finding a way to determine the slope.
4.- You should to get six consecutive straight lines right, without any mistakes.
Author: Juan Madrigal Muga
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| Ministerio de Educación, Cultura y Deporte. Aņo 2000 | ||