Thanks a lot. I guess I have to undo my Mathematica habits when working with SAGE, and think of the variables I WANT the result in, instead of the ones that I want eliminated.
Eric On Apr 21, 3:19 am, Jason Grout <[email protected]> wrote: > On 04/21/2010 02:12 AM, Jason Grout wrote: > > > > > On 04/20/2010 11:32 PM, eric948470 wrote: > >> Hello, > > >> Suppose I have several equations, > > >> f(a,b,c,d,e) == 0 > >> g(a,b,c,d,e) == 0 > >> h(a,b,c,d,e) == 0 > > >> Suppose I want to solve for a, but not have d and e in the solutions. > >> How would I do that? > > >> In Mathematica I would use, > > >> Solve[ { f(a,b,c,d,e)==0, g(a,b,c,d,e)==0, h(a,b,c,d,e)==0 }, a, > >> {d,e} ] > > >> How can I do this in Sage? > > >> I guess I have to use the 'solve' function, but I can't figure out > >> how. > > > Does this help? > > > sage: var('a,c,d,e') > > (a, c, d, e) > > sage: solve([a+c+d+e==0,a-c+2*d-2*e==2,2*a-c-d+3*e==3],[a,c,d]) > > [[a == -4/3*e + 1, c == -8/9*e - 1, d == 11/9*e]] > > Or rather, here is another example closer to an answer to your specific > question: > > sage: var('a,b,c,d,e') > (a, b, c, d, e) > sage: solve([a+b+c+d+e==0,a-+b^2+c+2*d-2*e==2,2*a-b-c-d+3*e==3],[a,d,e]) > [[a == 1/2*b^2 + b + 1/2*c + 5/2, d == -1/8*b^2 - 5/4*b - 9/8*c - 11/8, > e == -3/8*b^2 - 3/4*b - 3/8*c - 9/8]] > > Thanks, > > Jason > > -- > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group > athttp://groups.google.com/group/sage-support > URL:http://www.sagemath.org -- To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
