`collect`

Collects the terms of an expression by powers of a variable.

Category: Mathematics > Formula Manipulation and Simplification

Syntax

R = collect(p)

Collects in the default variable.

R = collect(p, x)

Collects in powers of x.

Description

collect does not change the value of the expression, only its form. Like terms in x are added, and each power of x is multiplied by a factored coefficient. It is the inverse view of expand: where expand removes parentheses, collect reorganizes by variable.

Input arguments

p: Symbolic expression or array of expressions.
x: Variable whose powers group the terms.

Output arguments

R: Equivalent expression written as a polynomial in x, with the other symbols inside the coefficients.

Example

Group by x

syms x y
collect(x^2*y + x*y + x^2 + 3, x)
collect((x+1)*(x+2) + x*y, x)

Output

ans = (y + 1)*x^2 + x*y + 3
ans = x^2 + (y + 3)*x + 2

collect