Hah, I love your CAD tool, but I am much more in love with your scopemeter. What a beauty!
(...)
If all you have is the RMS value of the AC component of the signal and the DC value, then that formula can be simplified. You don't need to know the frequency or the time. It just becomes VRMS = (VAC2+VDC2)0.5
Yep, frequency is not part of the RMS at all - I was carried away back then. Fancy tools at your disposal tend to do that to you.
I also have the RMS equations for triangular and square with DC levels, which are also useful to me.
(I love my 48GX! Both the physical and the soft versions)