(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Find the area of the surface obtained by rotating the curve about the x-axis:

y=cos 2x, 0<=x<=pi/6

2. Relevant equations

Surface area about the x-axis = Integral of 2pi * f(x) * sqrt(1+[f'(x)]^2) dx

3. The attempt at a solution

I think I set up my integral correctly, so my problem is figuring out how to solve the integral. I have:

2pi * Integral of cos 2x * sqrt(1+4sin^2 2x) dx on [0, pi/6]

I can't figure out how to solve that. And can someone teach me how to use Latex for integrals so it looks better.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Surface area of revolution

**Physics Forums | Science Articles, Homework Help, Discussion**