Is my graph scale correct? Please Help Me?

Question

Hi there. I just need to know if the scale I have on my cos graph is correct. The equation is 0.5cos 8x. Period = 2pie/8 = Pie/4.

The scale looks like this:

?? pie/16 pie/8 3pie/8 pie/4

Can someone please tell me what goes on the first point? Is it pie/32?

Btw graphs looks like this: http://education.yahoo.com/homework_help/math_help/solutionimages/miniprecalcgt/6/1/1/miniprecalcgt_6_1_1_8_50/f-460-26-ex-1.gif

Answer 1

Hi,

The period of your graph is π/4, as you stated.

It will help if you divide this period by 4 to get the "jump",. which is the horizontal distance to move from one key point of your cosine graph to another. In this case, the "jump" is (π/4) ÷ 4 = π/16.

Since there are no vertical or horizontal shifts, the normal starting point of cosine at (0,1) is shifted to (0,.5) because of amplitude being changed to .5. The 5 key points in the period of this graph are:

(0,.5), (π/16,0), (π/8,-.5), (3π/16,0), (π/4,.5) <==ANSWER

The x increases each time by the jump of π/16 and the y values vary by the amplitude of .5 from point to point.

I hope that helps!! :-)