Hi, I have an area between curves problem that I am stuck on and I think it is because I need to use a double-angle identity in my figuring of my intersection points, but I don't know how to to this when I have coefficients that are greater than 2.

Here is the problem:

Find the area between the following curves:

y=7cos(4x), y=7sin(8x) x=o x= pi/8

I am trying to find where the first two intersect:

7cos(4x) = 7sin(8x)

7cos(4x) - 7sin(8x) = 0 *I factored out the 7. Should I reduce the 4x to x and the 8x to 2x and then use the double angle identity for sin2x?

I keep getting my intersection as pi/2, which is not in the domain of the area limited by these curves.

Any help is greatly appreciated! Thanks!

Molly