MATLAB: Error : Function integration trapezoidal

areanumerical integrationtrapezoidal

i want to calculate area from numerical integration of function f(x) with the limits a to b and vary n . by the way i use this code from my handbook, numerical chapra. to solve my problem. but the result was error.
function I = trap(func,a,b,n,varargin)
% trap: composite trapezoidal rule quadrature
%   I = trap(func,a,b,n,p1,p2,...):
%                  composite trapezoidal rule
% input:
%   func = name of function to be integrated
%   a, b = integration limits
%   n = number of segments (default = 100)
%   p1,p2,... = additional parameters used by func
% output:
%   I = integral estimate
if nargin<3,error('at least 3 input arguments required'),end
if ~(b>a),error('upper bound must be greater than lower'),end
if nargin<4|isempty(n),n=100;end
x = a; h = (b - a)/n;
s=func(a,varargin{:});
for i = 1 : n-1
  x = x + h;
  s = s + 2*func(x,varargin{:});
end
s = s + func(b,varargin{:});
I = (b - a) * s/(2*n);
the error :
??? function I = trap(func,a,b,n,varargin)
    |
Error: Function definitions are not permitted in this context.
what should i do ?
— my purpose is to make the table like below this text, to known how the error result with vary n parameter.
%

Best Answer

Maybe following links are helpful for you for this purpose:
http://www.youtube.com/watch?v=qo3AtBoyBdM
http://www.youtube.com/watch?v=AzvOc5odmDg
These links shows how to use matlab functions. and how to input and get output values from them
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