1. The problem statement, all variables and given/known data Hi, Could you please help me decide on these answers? The question is " Are the following statements Sinusoidal? And are they Periodic? I have produced the waveforms in MathCad The limits are 0 - 4Pi 1.f(x)= sinx + 2sin(x-(Pi/6)) 2.f(x)= sinx +sin2x 3.f(x)= sinx + 1/2(sin2x) 4.f(x)= sinx + 1/3(sin3x)+1/5(sin5x) 5.f(x)= sinx.cos2x 6.f(x)= sin3x.sin2x 7.f(x)= sin^23x 2. Relevant equations 3. The attempt at a solution I think they are all periodic as my understanding of periodic is that the waveform repeats itself after 2pi (360 degrees) Which they all seem to do. I am unsure about the Sinusoidal part though. I know that number 1 is but not sure about the rest!! How do I tell? I also have to work out the r.m.s value of a complex waveform, Am I right in saying that if its sinusoidal I can use Vmax/root2? If its not sinusoidal can I use this formula?