# Question:Change coordinate systems for substitutions

## Question:Change coordinate systems for substitutions

Maple
Still being a newbie to Maple, I am stuck on this one. I am trying to create a general system of changing my equations in an [x,y] coordinate system to a [u,v] system. As a specific example: I have two substitution equations, u=2x-3y and v=-x+y. I have four equations: x=0, x=-3, y=x, y=x+1. I have tried MapToBasis with both static and procedure statements and I am not having any luck. The equations do not completely change to [u,v]. Here is one example: > proc (u, v) u = 2*x-3*y end proc; > proc (u, v) v = -x+y end proc; > with*VectorCalculus; > SetCoordinates('cartesian', [u, v]); > proc (x, y) x = -3 end proc; > proc (x, y) y = x+1 end proc; > MapToBasis(x, y, [u, v]); MapToBasis(-3, y, [-6 - 3 y, 3 + y]) > u[1]; (-6 - 3 y)[1] > proc (x, y) x = 0 end proc; > proc (x, y) y = x end proc; > MapToBasis(x, y, [u, v]); MapToBasis(-3, y, [-6 - 3 y, 3 + y]) > u[1]; (-6 - 3 y)[1] As you can see, u is still in terms of y and not v. Any suggestions would be appreciated. Thanks.
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