Learning Guide Learning Guide

5.3 Structural Manipulations • 187expr is a product of four factors.> op( expr );a, b, c, a bThe product a*b is not a factor in expr. You can make the substitutiona*b=3 in three ways: solve the subexpression for one of the variables,> subs( a=3/b, expr );3 c ( 3 b )buse a side relation to simplify,> simplify( expr, { a*b=3 } );3 c a bor use the algsubs command, which performs algebraic substitutions.> algsubs( a*b=3, expr);3 c a bNote that in the first case all occurrences of a have been replaced by3/b. Whereas, in the second and third cases both variables a and b remainin the result.You can make several substitutions with one call to subs.> expr := z * sin( x^2 ) + w;expr := z sin(x 2 ) + w> subs( x=sqrt(z), w=Pi, expr );z sin(z) + πThe subs command makes the substitutions from left to right.