# Function function/ passing function/ varargin help?

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Gabrielle Bartolome on 24 Oct 2020
Commented: Stephen Cobeldick on 26 Oct 2020
Develop a function function M-file that returns the difference between the passed function's maximum and minimum value given a range of the independent variable. In addition, have the function generate a plot of the function for the range. Test it for the following cases:
f(t) = a*exp^(-b*t)*sin(t-c) from t = 0 to 6*pi
1. a = 8, b = 0.25, c = 2 below is what I have so far. I keep getting an error. I don't know what I am doing wrong. .I would appreciate any help that you could provide. Thank you.
%input:
% a = lower bound of range
% b = upper bound of range
% n = number of intervals
%output:
% fdiff = difference between max and minimum of a function
function fdiff = funcdiff(f, a, b, n, varargin)
x = linspace(a,b,n);
y = f(x, varargin{:});
fdiff = max(y) - min(y);
fplot(f, [a b], varargin{:})
end
% clear clc
% diff = @(t) a*exp^(-b*t)*sin(t-c);
% funcdiff(diff, 0, 6*pi, 180, 8, 0.25, 2)

#### 1 Comment

Stephen Cobeldick on 26 Oct 2020

KSSV on 24 Oct 2020
Edited: KSSV on 24 Oct 2020
a = 8 ;
b = 0.25 ;
c = 2 ;
n = 180 ;
f = @(t) a*exp(-b*t).*sin(t-c);
t = linspace(a,b,n);
y = f(t);
fdiff = max(y) - min(y);
plot(t,y)

Gabrielle Bartolome on 24 Oct 2020
I am not sure I really understand the code you placed. It seems to work by itself but not as a funciton function and it doesn't use varargin.
Cole Fontana on 26 Oct 2020
Don't worry I'm just as stuck as you are lol
Professor Huang said that we can't use fplot when using varagin.