Solved
Total Harmonic Distortion of AC current using Fourier Analysis
So, I've been able to work through all the values so far but seems like I have a problem with the summation notation since the THD of alpha does not converge to a solution:
Not sure why, but the problem is "only" n=2 and function I.a
The function you integrate does not look malicious
Some additional observations:
EDIT:
Solution - Set the system variable TOL to a lower value. Either write TOL:=10^-8 at the top of the sheet in front of the function definitions or use the menu.
Doing so makes the integral converge
The plot below with variable values of alpha takes very long. I stopped it and used a larger step width to speed it up.
It looks like THD is independent from alpha
