Not long ago, I asked such a question, Refer to the link below
thank you very much for your help！Special thanks to vv.
Actually, the problem I'm having is a complex expression like this:
q^r*product((q^(n - 1) - q^(i - 1))^2, i = 1 .. r)*(q^(-2 + 2*n - r) - 2*q^(n - 1) + 1)/product(q^r - q^i, i = 0 .. r - 1) - q^(r - 1)*product((q^(n - 1) - q^(i - 1))^2, i = 1 .. r - 1)*(q^(2*n - 1 - r) - 2*q^(n - 1) + 1)/product(q^(r - 1) - q^i, i = 0 .. r - 2)
I tried to simplify it, but It didn't work that well.
I always feel that this formula can be further simplified, but there is no way to start. Of course, My thoughts maybe incorrect. maybe this is the simplest form.