# Homework Help: Computing Arc Length and Cannot Solve the Integral

1. Feb 3, 2012

### Voodoo583

1. The problem statement, all variables and given/known data

Find the length of the polar curve.

Complete the cardioid r=1+cosθ

2. Relevant equations

L=∫αβ√[f(θ)2+f'(θ)2] dθ

3. The attempt at a solution

Given f(θ)2 is equal to cos2θ+2cosθ+1

and f'(θ)2=sin2θ

I arrive at the integral ∫αβ√[2cosθ+2] dθ which I cannot for the life of me solve for. It's been a while since my calc II class so I flipped through my textbook to see if I could find a solution. I cannot do u substitution as far as I can tell nor integration by parts and I couldn't find anything similar to the form above in the table of integrals.

2. Feb 3, 2012