Question

Find the area of the specified region shared by the circles r = 4 and r = 8sin

Answer 1

Ind the area shared by the circles r=2cos(theta) and r=2sin(theta).

i know the general formula for finding the area, but i don't know which is the outside one, and which is the inside circle. but i've tried both ways and am still not getting the right answer. 

so let's just say i'll try it with integral .5(4cos(x)^2-.5(4sin(x)^2)
i can factor out a 2, giving me cos(x)^2-sin(x)^2. the integral of that, i believe, can be expressed as 4sin(2x). now i figured the limits of integration were from 0 to pi/4, because those are the two places the circles intersect. so evaluating there, i would get 4-0=4. but I've been told the answer is pi/2 -1. so where am i going wrong, because i'm way off.