2021-05-26 23:02:02 +0100 received badge ● Famous Question (source) 2018-03-21 14:17:35 +0100 received badge ● Student (source) 2017-02-04 20:47:16 +0100 received badge ● Notable Question (source) 2015-10-23 09:29:00 +0100 received badge ● Famous Question (source) 2013-07-27 19:17:58 +0100 received badge ● Notable Question (source) 2013-05-29 01:24:41 +0100 received badge ● Popular Question (source) 2012-05-07 16:55:32 +0100 received badge ● Popular Question (source) 2011-06-24 07:54:32 +0100 marked best answer how to properly substitute in a matrix? Try this: sage: solutions=solve(list(f.diff()),[x,y],solution_dict=True) sage: solutions [{y: 0, x: -I}, {y: 0, x: I}, {y: -1/2, x: 0}] sage: H.subs(solutions[2]) [(x, y) |--> -1 (x, y) |--> 0] [ (x, y) |--> 0 (x, y) |--> 2]  Or this: sage: H(x,y).subs(solutions[2]) [-1 0] [ 0 2]  I'm not sure exactly what output you are looking for. The documentation for solve has some more information about this keyword. 2011-06-24 07:54:23 +0100 commented answer how to properly substitute in a matrix? Thanks, kcrisman! Maybe it is possible to include these lines into Sage Reference Manual? In the manual one enters the point manually... I don't know how to do this... 2011-06-24 07:52:04 +0100 commented answer how to properly substitute in a matrix? Thanks, niles! 2011-06-23 13:12:36 +0100 asked a question how to properly substitute in a matrix? Let's consider a modified example from Sage reference manual f(x,y)=x^2*y+y^2+y solutions=solve(list(f.diff()),[x,y]) the_solution=solutions[2] H=f.diff(2); # Hessian matrix  How can i properly substitute the_solution into H? I have tried: H(x,y).subs(the_solution) - does not work. This will work for H(x,y).subs(x==0) H(x,y).subs_expr(*the_solution) - does not work. This will work for f(x,y).subs_expr(*the_solution) 2011-06-18 11:49:10 +0100 commented answer latex typesetting for derivatives like g' Thanks! Will try... 2011-06-18 11:48:50 +0100 received badge ● Supporter (source) 2011-06-18 11:48:47 +0100 received badge ● Scholar (source) 2011-06-18 11:48:47 +0100 marked best answer latex typesetting for derivatives like g' You can try to apply the patch attached to ticket #6344. The patch review walk through contains instructions on how to apply patches. 2011-06-17 14:29:02 +0100 asked a question latex typesetting for derivatives like g' When i try: f(x) = function('f',x) g = diff(f(x),x) latex(g)  i get: D[0]\left(f\right)\left(x\right)  but i would like to get something like: g'\left(x\right)  How can i do this with Sage?