MATLAB Mathematics - SERC - Index of

Representing Functions in MATLAB
Representing Functions in MATLAB
MATLAB can represent mathematical functions by expressing them as
MATLAB functions in M-files or as anonymous functions. For example,
consider the function
1
fx ( ) = ------------------------------------------
( x – 0.3) 2 + 0.01
1
+ ------------------------------------------
( x – 0.9) 2 – 6
+ 0.04
This function can be used as input to any of the function functions.
MATLAB Functions
You can find the function above in the M-file named humps.m.
function y = humps(x)
y = 1./((x - 0.3).^2 + 0.01) + 1./((x - 0.9).^2 + 0.04) - 6;
To evaluate the function humps at 2.0, use @ to obtain a function handle for
humps, and then use the function handle in the same way you would use a
function name to call the function:
fh = @humps;
fh(2.0)
ans =
-4.8552
Anonymous Functions
A second way to represent a mathematical function at the command line is by
creating an anonymous function from a string expression. For example, you
can create an anonymous function of the humps function. The value returned,
fh, is a function handle:
fh = @(x)1./((x-0.3).^2 + 0.01) + 1./((x-0.9).^2 + 0.04)-6;
You can then evaluate fh at 2.0 in the same way that you can with a function
handle for a MATLAB function:
fh(2.0)
ans =
-4.8552
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