Comment #2 on issue 1338 by smichr: assert poly is not None in solve http://code.google.com/p/sympy/issues/detail?id=1338
The 1398 modification works but a spurious root (r==0) is introduced (I believe) when finding the common denominator. >>> r=symbols('r') >>> solve(diff((a/r)**12-2*(a/r)**6,r),r) Got strategy 1 >>> 1 Got strategy 0 >>> 0 [0, -(a_**6)**(1/6)/2 + I*3**(1/2)*(a_**6)**(1/6)/2, (a_**6)**(1/6)/2 - I*3**(1/2)*(a_**6)**(1/6)/2, (a_**6)**(1/6)/2 + I*3**(1/2)*(a_**6)**(1/6)/2, -(a_**6)**(1/6)/2 - I*3**(1/2)*(a_**6)**(1/6)/2, -(a_**6)**(1/6), (a_**6)**(1/6)] >>> len(_) 7 -- You received this message because you are listed in the owner or CC fields of this issue, or because you starred this issue. You may adjust your issue notification preferences at: http://code.google.com/hosting/settings --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to sympy-issues@googlegroups.com To unsubscribe from this group, send email to sympy-issues+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en -~----------~----~----~----~------~----~------~--~---