
Re: Symbolic manipulation with Sqrt[1] ?
Posted:
Dec 7, 2009 11:20 AM


Axel Vogt schrieb: > > In Maple (which  to answer your latter question  is not free of > strange behaviours): > > eval( (a+b*I)/(cI*d), I=I ); > > a  b I >  > c + d I > > There is a (nonrecursive) command 'substitute' as well, it would do > here. > > For the other example given by Richard Fateman: > > simplify( x^2, {x^2=y^4} ); > 4 > y > > This is called 'simplification with side relations' (=w.r.t > equations). > > It however would not work for simplify( 1/sqrt(x^3), {sqrt(x^3)=y} ), > the command needs polynomial relations. > > And it does not work for constants like simplify( 1/sqrt(2), {2=y^2} > ).
Do I understand you correctly that it is impossible in Maple to substitute something for arbitrary subexpressions? Are only variables (and predefined constants like I) allowed? Would
eval( 1/x^2, x^2 = y^4 );
or
eval( 2*cos(x^2), cos(x^2) = sin(y) );
be forbidden syntactically?
Martin.

