FUNCTIONS AND GRAPHS V

Activities with linear functions

Which straight line is it?

the purpose of the next game is to find a way to determine the slope of the orange straight line. 

You should bear in mind the following rules:

- You can only guess each straight line once, because on doing so the orange line changes place, although on moving it leaves a shadow which is useful for checking if you were close.

- If you get it completely right the shadow will not be seen, but will remain covered by the blue line.

- You can rub out the previous shadow by clicking on the coordinate system with the secondary mouse button, but your guesses will also be deleted.

1.- Investigate the slope of the orange straight line and make a guess: write it on the blue equation and press the [Return] key. You should manage six consecutive correct answers.  But before you start, read the following advice:

- Notice first whether the slope is positive or negative. If it is positive ask if it should be greater or less than 1.  In the case of it being negative, see if the slope is greater or less than -1.

- Watch the co-ordinates of the white point and use them ...

Another straight line?

This game is similiar to the previous one, with the same rules.

2.- Investigate the slope of the orange straight line and make a guess. Watch the co-ordinates which are obtained on clicking the main button of the mouse on the straight line.  You should get six consecutive correct answers.

Which straight line passes through ...?

Now you must determine the slope of a straight line which passes through an indicated point.  In this case the point has whole number co-ordinates and the solution should be exact.

3.- Investigate the slope of the straight line that passes through the orange point and make a guess. (You can write decimal numbers and also fractions, for example: y=3/5*x).

You should get 6 consecutive correct answers.

What straight line passes through ...?

Now find the slope of the straight line that passes through a point, in this case with arbitrary co-ordinates.

4.- You should manage to touch on six consecutive points with the straight lines, without any mistakes inbetween. 

Angle of a straight line with the positive X axis.

The angle that forms a straight line with the positive X axis is closely related to its slope.  The value of the slope of the straight line coincides with what is called the tangent of the angle that forms the straight line with the posite X axis.

5.-Observe the value of the angle for different straight lines in all quadrants. (Move the red point dragging with the mouse.)

Write down the slopes of the straight lines for the following angles:

Author: Juan Madrigal Muga

	Ministerio de Educación, Cultura y Deporte. Año 2000