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polyval
Polynomial evaluation
y = polyval(p,x) [y,delta] = polyval(p,x,S)
y = polyval(p,x)
returns the value of the polynomial p
evaluated at x
. Polynomial p
is a vector whose elements are the coefficients of a polynomial in descending powers.
x
can be a matrix or a vector. In either case, polyval
evaluates p
at each element of x
.
[y,delta] = polyval(p,x,S)
uses the optional output structure S
generated by polyfit
to generate error estimates, y
±delta
. If the errors in the data input to polyfit
are independent normal with constant variance, y
±delta
contains at least 50% of the predictions.
The polyvalm(p,x)
function, with x
a matrix, evaluates the polynomial in a matrix sense. See polyvalm
for more information.
The polynomialp = [3 2 1]; polyval(p,[5 7 9])which results in
ans = 86 162 262For another example, see
polyfit
.
polyfit
Polynomial curve fitting
polyvalm
Matrix polynomial evaluation