Calculating the Length of a Curve with Calculus

[MozAngeles]

Homework Statement

i'm studying for an exam. and I'm pretty sure i know how do do these types of problems. this is aneven problem in the book so i wanted to know if my answer is right.

Find the length of the curve for $$r=\sqrt{1+\cos2\theta} , \pi/2\leq\theta\leq\pi/2$$

Homework Equations

integral of [tex]\sqrt{(r^2+(dr/d\theta)^2}[\tex]

The Attempt at a Solution

i simplified my r to be $$\sqrt{2}*\cos\theta$$
after simplification and plugging into the formula. i got my answer to be $$\sqrt{2}*\pi$$

 

[ideasrule]

I got the same result. I'm known for making tons of algebra mistakes, so trust my algebra at your own risk.