MATLAB Mathematics - SERC - Index of

Parameterizing Functions Called by Function Functions
You can call findzero with any values of the coefficients b and c, which are
seen by poly because it is a nested function.
As an example, to find a zero of the polynomial with b = 2 and c = 3.5, using
the starting point x0 = 0, call findzero as follows.
x = findzero(2, 3.5, 0)
This returns the zero
x =
-1.0945
Providing Parameter Values to Anonymous
Functions
Suppose you have already written a standalone M-file for the function poly
containing the following code, which computes the polynomial for any
coefficients b and c,
function y = poly(x, b, c) % Compute the polynomial.
y = x^3 + b*x + c;
You then want to find a zero for the coefficient values b = 2 and c = 3.5. You
cannot simply apply fzero to poly, which has three input arguments, because
fzero only accepts functions with a single input argument. As an alternative
to rewriting poly as a nested function, as described in “Providing Parameter
Values Using Nested Functions” on page 4-30, you can pass poly to fzero as a
function handle to an anonymous function that has the form
@(x) poly(x, b, c). The function handle has just one input argument x, so
fzero accepts it.
b = 2;
c = 3.5;
x = fzero(@(x) poly(x, b, c), 0)
This returns the zero
x =
-1.0945
4-31