# Integrals, Physics

1. Sep 19, 2005

### tmc

I have this formula, and I just cant seem to be able to find any sensible answer:

$$V^2_\textrm{rms}=\frac{1}{T}\int_{0}^{T}V^2_0sin^2(2ft\pi)dt$$

Depending on what I do, I either get an obviously wrong answer, 0, or $$V_0$$.

Last edited: Sep 19, 2005
2. Sep 19, 2005

### George Jones

Staff Emeritus
The stuff under the integral sign needs to be squared. This is the S part of rms.

Regards,
George

3. Sep 19, 2005

### tmc

yeah, my bad. Edited it.
Still dont get how to solve it though.

4. Sep 19, 2005

### George Jones

Staff Emeritus
Use $cos(2\theta) = 1 - 2sin^2 (\theta)$ and $f = 1/T$.

Regards,
George