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polyval

Evaluating Polynomial

polyval(p, x)

  • It evaluates a polynomial at each element of x. The coefficients of the polynomial are contained in p.
  • x should be an array.
  • p should be a vector containing coefficents of a polynomial; p(1) corresponds to the highest order term.
  • p should be non-empty.
  • If p is a logical or character array, it is converted to a double array before executing the function.
  • The output has the same size as x.

Example 1: Plotting a polynomial.

r=[2 3 4 5];
% Creating a polynomial with roots r
p=poly(r);
x=linspace(1.8,5.2);
% Evaluating the polynomial
y=polyval(p,x);
plot(x,y,'-o','MarkerSize',2)
Plot is generated.

Plot