Hello, I am a new sympy user and am trying to work out a derivation using IPython3 in a notebook.
I have an expression: a_k = Sum(-q_i*z_i/k,(i,1,m)). I want a_k.diff(z_i), however the Sum gets evaluated and I get m*(otherwise correct stuff), and of course the sum goes away. I thought that using Sum() instead of summation(), the expression would not evaluate. I guess .diff() causes the expression to evaluate? Is there a way around this problem? If it was this one expression I would just make temp = stuff_inside_sum and .diff() that, but it is nested in yet another Sum(). Eg. phi = Sum(a_k/x,(k,1,oo)). Any help would be appreciated, Thanks! -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
