Thanks for the help guys. Here's how I did it.
I expanded v_{rms}(t)^2 to:
v_{rms}(t)^2 = 5^2 + 30 \cos{(t+10^o)} + 10 \cos{(2t+30^o)} +9 \cos^2{(t+10^o)} + 6 \cos{(t+10^o)} \cos{(2t+30^o)} + \cos^2{(t+10^o)}
and using the product to sum identity:
\cos{x} \cos{y} = \frac{1}{2} (\cos{(x-y)}...
Homework Statement
The voltage across a resistor is given by:
v(t) = 5 + 3 \cos{(t + 10^o)} + \cos{(2 t + 30^o)} V
Find the RMS value of the voltage
Homework Equations
For a periodic function, f(t), the rms value is given by:
f_{rms} (t) = \sqrt{\frac{1}{T} \int_{0}^{T} f(t)^2 dt}
Where T...