Hi,

In the case of a sine waveform, the RMS value is just the amplitude divided by the square of 2.

In your case it's about 7 and 14.

Hope it helps

thank you. but how can i calculate in case of  cos?

i.e.   A sin(omega*t +pi/2)

this also same as per you said (A/root square of 2) or vary? please suggest me.

it's the same.

The RMS value is calculated over a period and sin and cos have the same waveform over a period.