Using the solution of equation

 6 How can I use after solve(eq) the result? For example, the result for this simple linear system [x + 2*y + 4*z - 1] [ x + 4*z - 5] [ 3*x + 6*z - 6]  is [[x == -1, y == -2, z == (3/2)]]  How can I use x,y,z in an expression, say x^2+y^2+z^2 ? asked Oct 18 '10 czsan 153 ● 1 ● 7 ● 16 Kelvin Li 443 ● 10 ● 17

 7 The easiest way is to pass solution_dict=True to the solve command. sage: var('x,y,z') (x, y, z) sage: eqs = [x + 2*y + 4*z - 1 == 0, x + 4*z - 5 == 0, 3*x + 6*z - 6] sage: solve(eqs, (x,y,z)) [[x == -1, y == -2, z == (3/2)]] sage: sols = solve(eqs, (x,y,z), solution_dict=True); sols [{z: 3/2, y: -2, x: -1}]  Then, you can pass that dictionary into the subs method of your expression. For example, sage: f = x^2 + y^2 + z^2 sage: [f.subs(sol) for sol in sols] [29/4]  posted Oct 18 '10 Mike Hansen 3840 ● 21 ● 46 ● 84 Thank you, it seems to good. czsan (Oct 18 '10)

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