Use expr2.doit(). Aaron Meurer
On Wed, Jan 28, 2015 at 10:43 PM, <[email protected]> wrote: > How do I get Derivative(0,t) simplified? In my code below, I used subs to > substitute 0 for b(t) in a formula, > a(t)*Derivative(b(t), t) + Derivative(a(t), t) > > Then I got > > a(t)*Derivative(0, t) + Derivative(a(t), t) > > > whereas the answer I want is: > > Derivative(a(t), t) > > > ------------ > > from sympy import * > from sympy.physics.vector import * > from sympy.physics.mechanics import * > > a=dynamicsymbols('a') > a_d=dynamicsymbols('a',1) > b=dynamicsymbols('b') > b_d=dynamicsymbols('b',1) > > expr = a*b_d + a_d > print expr > expr2 = expr.subs(b, 0) > print expr2 > print simplify(expr2) > ------------ > > Thank you, > Iai > > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/9670822f-1eb8-4946-96e1-4361de271b93%40googlegroups.com > <https://groups.google.com/d/msgid/sympy/9670822f-1eb8-4946-96e1-4361de271b93%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6Jq7k-UtotVS%2BKR1C6TuU7%2B%2B%3DSJdCvQuuhu%3Dns0v4WpXA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
