Learning Guide Learning Guide

5.3 Structural Manipulations • 179fract :=1 + sin(x) 3 − y xy 2 − 1 + x> numer( fract );x + sin(x) 3 x − y> denom( fract );x (y 2 − 1 + x)Consider the expression> expr := 3 + sin(x) + 2*cos(x)^2*sin(x);expr := 3 + sin(x) + 2 cos(x) 2 sin(x)The whattype command identifies expr as a sum.> whattype( expr );‘ + ‘Use the op command to list the terms of a sum or, in general, theoperands of an expression.> op( expr );3, sin(x), 2 cos(x) 2 sin(x)The expression expr consists of three terms. Use the nops commandto count the number of operands in an expression.> nops( expr );3You can select, for example, the third term as follows.> term3 := op(3, expr);