Learning Guide Learning Guide

188 • Chapter 5: Evaluation and Simplification> subs( z=x, x=sqrt(z), expr );√ z sin(z) + wIf you give a set or list of substitutions, subs makes those substitutionssimultaneously.> subs( { x=sqrt(Pi), z=3 }, expr );3 sin(π) + wNote that in general you must explicitly evaluate the result of a callto subs.> eval( % );wUse the subsop command to substitute for a specific operand of anexpression.> expr := 5^x;expr := 5 x> op( expr );5, x> subsop( 1=t, expr );t xThe zeroth operand of a function is typically the name of the function.> expr := cos(x);expr := cos(x)> subsop( 0=sin, expr );