Math domain error

Question

I am wrote code and i am had an a error, "Math domain error", why? How to fix it?
https://code.sololearn.com/cU7NtZgaY2d2/?ref=app

Answer 1

it's because : list.append(num-i)
will result in negative numbers
num2 is negative by the last assignment, math.sqrt(num2) is a complex number.