Is a sinewave that is present entirely within the positive domain DC? How to calculate Vrms for a DC offset sinewave?
for a sine wave \$V_{ac~rms}=\dfrac{V_p}{\sqrt{2}}\$
Vac signal with DC offset = \$\sqrt{V_{dc~rms}^2+V_{ac~rms}^2}=\sqrt{V_{dc}^2+\dfrac{V_p^2}{2} }\$