I perform some calculations with maxima and I would like to isolate a specific part of an expression at the left hand side of the equality and push the rest to the right hand side.
For an example I would like to isolate x^2+y^2 in the following expression :
(%i1) expand((x-x1)^2 + (y-y1 )^2 = r1^2);
(%o1) y1^2-2*y*y1+y^2+x1^2-2*x*x1+x^2=r1^2
and I would like to have :
(%o1) y^2+x^2=r1^2+2*x*x1-x1^2+2*y*y1-y1^2
I thought using algsys to do that but it's clearly not the right function :
(%i3) algsys ([expand((x-x1)^2 + (y-y1 )^2 = r1^2)], [x^2+y^2]);
(%o3) []
(%i4) algsys ([expand((x-x1)^2 + (y-y1 )^2 = r1^2)], [x]);
(%o4) [[x=sqrt(-y1^2+2*y*y1-y^2+r1^2)+x1],[x=x1-sqrt(-y1^2+2*y*y1-y^2+r1^2)]]
Do you know how to isolate specific terms in a expression with maxima ?