Hello, I'm reposting this 'cause I think it's more relevant here than where it was posted before. Not sure how to delete the other one... I'm trying to plot the heat capacity as a function of the temperature from some small temperature to Debye's using numerical summation over the energy (shown in the photo below). However, I'm struggling to determine the boundary of k (actually, of all three since there are 3 sums). I'm using Maple for those wondering. I'd be more than happy if someone could help me out with that. Thank you in advance.