# Thread: Cosine Functions: Altering dimensions/scaling

1. ## Cosine Functions: Altering dimensions/scaling

a[cos(bx + c)] + d

There are two cosine functions. One is higher than the other. There is a fixed domain such as 10 < x < 10 so that the area between the curves creates an image.

How do I, for example, double the dimensions of this image? And how can I play around with the variables of each curve to create any image size that I want?

2. any guess?

3. a controls the height of the function
b controls the period, or how long it takes to complete a cycle
c moves the graph to the left or right
d moves the graph up or down.

4. Originally Posted by terr13
a controls the height of the function
b controls the period, or how long it takes to complete a cycle
c moves the graph to the left or right
d moves the graph up or down.
Yes, thank you. Now I need to figure out how to double the size of an image. Let me give you an example:

3cos(2x-2)+3
and
3cos(2x-2)+6
where the domain is 0 to 4.
This creates like a tilted 'N' shape between the two curves. How can I double this image?

5. So we cannot change the domain or can we?

6. You can change the domain if you are trying to double the size of the image. I asume the domain will be twice as big(?) Sorry for not being clear

7. Then double the image = double the height and double the width? Width in this case is the period. Double a and double b.

8. Woops, to double the period you need to halve b.