RE.wnat is rms value

Root of the Mean of the Square
You must first square the sine, this will give you a sine at twice the
"frequency", sin^2a = .5(sin2a + 1)
This result is a sine wave that has a minimum value of 0 and a max of
1
The mean by inspection is .5
The sqrt of .5 is 1/sqrt2
Can read from 40tude but only able to post via google, hence the RE
Explained this once by getting the questioner to draw it on a bit of
graph paper, he got it at once.

 

Oops should be .5(1-cos2a)