`poly2sym`

Builds a symbolic polynomial from a coefficient vector.

Category: Symbolic Computations in MATLAB > Conversion Between Symbolic and Numeric

Syntax

p = poly2sym(c)

Polynomial in the default variable x, with coefficients c, highest power first.

p = poly2sym(c, v)

Uses the symbolic variable v instead of x.

Description

The coefficient order is the same as polyval, roots and poly: the first entry multiplies the highest power. Numeric coefficients are converted to exact rational numbers, so 0.5 gives 1/2 instead of a decimal. Leading zeros are dropped.

It is the inverse of sym2poly.

Input arguments

c: Vector of coefficients, numeric or symbolic.
v: Symbolic variable or its name (optional).

Output arguments

p: Symbolic polynomial c(1)*v^(n-1) + ... + c(n).

Example

Default and named variable

poly2sym([1 0 -1])
syms t
poly2sym([2 3], t)
poly2sym([1 0.5 0.25])

Output

ans = x^2 - 1
ans = 2*t + 3
ans = x^2 + x/2 + 1/4

poly2sym