# Integrals, Physics

tmc
I have this formula, and I just can't 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:

## Answers and Replies

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

Regards,
George

tmc
yeah, my bad. Edited it.
Still don't get how to solve it though.

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

Regards,
George