### Home > APCALC > Chapter 11 > Lesson 11.2.2 > Problem11-57

11-57.

Calculate the area inside both $r = 4\cos\left(θ\right)$ and $r = 4\sin\left(θ\right)$. 11-57 HW eTool (Desmos). Homework Help ✎

Determine the bounds by solving 4cos(θ) = 4sin(θ).

By looking at the graph, you can calculate the area inside of r = sin(θ) for 0 ≤ θπ/4 and double it.

$2\int_{0}^{\pi/4}\frac{1}{2}(4\sin(\theta))^2d\theta$

$8\sin^2(\theta)=4-4\cos(2\theta)$