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Scilab Help >> Polynomials > inv_coeff

# inv_coeff

build a polynomial matrix from its coefficients

### Syntax

```P = inv_coeff(C)
P = inv_coeff(C, d)
P = inv_coeff(C, d, varname)```

### Arguments

C

a big matrix of the coefficients

d

a polynomial matrix degree. The optional parameter with default value `d=-1+size(C,'c')/size(C,'r')`

varname

a string giving the polynomial variable name (default value `'x'`).

### Description

`P=inv_coeff(Mp,k)`, when `k` is compatible with `Mp` size, returns a polynomial matrix of degree `k`. `C=[C0,C1,...,Ck]` and `P= C0 + C1*x +... +Ck*x^k`.

### Examples

```A = int(10*rand(2,6))
// Building a degree 1 polynomial matrix
P = inv_coeff(A,1)
norm(coeff(P)-A)
// Using default value for degree
P1 = inv_coeff(A)
norm(coeff(P1)-A)```

• poly — Polynomial definition from given roots or coefficients, or characteristic to a square matrix.
• degree — degree of polynomial matrix
• coeff — polynomial coefficients