I only need help with part C). What I've done for part B) is square the wave, which makes Vpeak->V^2peak and the waveform in the negative region(under the period axis) become positive AND squared(like the waveform from 3T to 5T). I know Vpk=sqrt(2)Vrms, but that, of course, won't give maximum marks. So I equaled Vrms=sqrt(1/8T(total period) times the areas under the waveform graphs)=V/(sqrt(2))=140(sqrt(2))=198V
C) wants us to to find the pk Voltage to get the same 140V rms value, which is again 198V. My question is: How do we find the area under the graph?. We square the wave as before, obtaining the negative cycle as a squared positive one. I see we have 2 flipped parabolas. I think we can solve this using a definite integral, but that's where I get stuck and can't get the 198V answer.