## Polynomials

Polynomials, like everything else in Matlab, is represented as a vector. The polynomial

```                                   3
3 x  - 4 x + 5
```

is represented by the vector [3, 0, 4, 5].

Polynomial functions are:

conv Compute the product of two polynomials conv( [3 5 2], [3 0 0 2 3] )
deconv Compute the quotient and remainder as a result of dividing the 1st polynomial by the 2nd deconv( [3 0 0 2 3], [3 5 2] )
poly Create a polynomial having the given roots poly( [3 5 2 3] )
polyder Differentiate the given polynomial polyder( [3 5 2 3] )
polyval Evaluate the polynomial at a point or points polyval( [3 5 2 3], 3.235 )
polyvalm Evaluate the polynomial at a matrix polyvalm( [3 5 2 3], [1 2; 3 5] )
polyfit Fit a polynomial to a set of points polyfit( [1 2 3 5], [3 5 4 7], 3 )
roots Find the roots of the given polynomial (including multiple roots.) roots( [5 3 0 0 2] )

### polyval

To evaluate the polynomial at a point, use the polyval function:

```>> polyval( [3, 0, 4, 5], 3.2 )

ans =

116.1040

>> 3*3.2^3 + 4*3.2 + 5

ans =

116.1040

```

### polyvalm

To subsitute a matrix into a polynomial and evaluate it, use the polyvalm function:

```>> A = [1 2; 3 4]
>> polyvalm( [3, 0, 4, 5], [1 2; 3 4] )

ans =

120   170
255   375

>> 3*A^3 + 4*A + 5*eye(2)

ans =

120   170
255   375

```