Symbolic Math Toolbox™

poly2sym - Polynomial coefficient vector to symbolic polynomial

Syntax

r = poly2sym(c)
r = poly2sym(c, v)

Description

r = poly2sym(c) returns a symbolic representation of the polynomial whose coefficients are in the numeric vector c. The default symbolic variable is x. The variable v can be specified as a second input argument. If c = [c1 c2 ... cn], r = poly2sym(c) has the form

poly2sym uses sym's default (rational) conversion mode to convert the numeric coefficients to symbolic constants. This mode expresses the symbolic coefficient approximately as a ratio of integers, if sym can find a simple ratio that approximates the numeric value, otherwise as an integer multiplied by a power of 2.

r = poly2sym(c, v) s a polynomial in the symbolic variable v with coefficients from the vector c. If v has a numeric value and sym expresses the elements of c exactly, eval(poly2sym(c)) returns the same value as polyval(c, v).

Examples

poly2sym([1 3 2]) returns

x^2 + 3*x + 2

poly2sym([.694228, .333, 6.2832]) returns

6253049924220329/9007199254740992*x^2+333/1000*x+3927/625

poly2sym([1 0 1 -1 2], y) returns

y^4+y^2-y+2

See Also

sym, sym2poly, polyval in the online MATLAB^® Function Reference

poly

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