poly
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Name

poly — polynomial definition

Calling Sequence

p=poly(a,vname, ["flag"])

Parameters

a

matrix or real number

vname

String, the symbolic variable name. If the string have more than 4 characters only the first 4 are taken into account.

"flag"

string ("roots", "coeff"), default value is "roots".

Description

If a is a matrix,

p is the characteristic polynomial i.e. determinant(x*eye()-a), x being the symbolic variable.

If v is a vector,

  • poly(v,"x",["roots"]) is the polynomial with roots the entries of v and "x" as formal variable. (In this case, roots and poly are inverse functions). Note that Infinite roots gives zero highest degree coefficients.

  • poly(v,"x","coeff") creates the polynomial with symbol "x" and with coefficients the entries of v (v(1) is the constant term of the polynomial). (Here poly and coeff are inverse functions).

s=poly(0,"s") is the seed for defining polynomials with symbol "s".

Examples

    
    s=poly(0,"s");p=1+s+2*s^2;
    A=rand(2,2);poly(A,"x")
    //rational fractions
    h=(1+2*%s)/poly(1:4,'s','c')

See Also

coeff , roots , varn , horner , derivat , matrices , rational
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