## POLYVAL Evaluate Polynomial Fit at Selected Points

Section: Optimization and Curve Fitting

### Usage

The`polyval`

routine has the following syntax
y = polyval(p,x)

where `p`

is a vector of polynomial coefficients,
in decreasing degree (as generated by `polyfit`

, for example).
If `x`

is a matrix, the polynomial is evaluated in the matrix
sense (in which case `x`

must be square).

### Function Internals

The polynomial is evaluated using a recursion method. If the polynomial is

then the calculation is performed as

### Example

Here is a plot of`x^3`

generated using polyval
--> p = [1 0 0 0] p = 1 0 0 0 --> x = linspace(-1,1); --> y = polyval(p,x); --> plot(x,y,'r-')

Here is the resulting plot