- #1

kostoglotov

- 234

- 6

## Homework Statement

imgur link: https://i.imgur.com/9jozS67.png

## Homework Equations

## The Attempt at a Solution

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Shouldn't I use [itex]V_{rms} = \sqrt{\frac{1}{T}\int_T v^2 dt}[/itex]?

Which would be

[tex]\sqrt{\frac{100}{2\pi}\int_0^{2\pi/100}(20+60cos(100t))^2dt}[/tex]

This equals [itex]\approx 79.88 V[/itex]

The answer is given as [itex]\approx 46.9V[/itex] and the solution manual shows the following working

[tex]\sqrt{20^2 + \frac{60^2}{2}}[/tex]

Why do they apply that solution and not the one I used?