I am trying to find the positive roots of the equaiton y = ((exp(1).^​(-0.2*x)))​*(cos(2*x)​)-(0.15*x.​^2)+1, but I keep getting the error message saying that there arent enough input arguments. I dont know what to do.

This is what I enter in my Editor window verbatim:

function y = f(x)
y = ((exp(1).^(-0.2*x)))*(cos(2*x))-(0.15*x.^2)+1;
fun=@f; % function
x0= [3,4]; % initial interval
x= fzero(fun,x0);

This is what I receive in the Command window after I run the function:

>> f Error using f (line 2) Not enough input arguments.

[John D'Errico]

I do wonder why anyone would use a form like

exp(1).^(-0.2*x)

instead of the mathematically identical

exp(-0.2*x)

Answer 1

[Alberto]

http://www.mathworks.com/matlabcentral/answers/72291-how-do-i-find-all-the-positive-roots-of-e-2x-cos-2x-15x-2-1

Answer 2

[Walter Roberson]

The lines starting from "fun=" should be in a different file, or entered in the command line, and you would run that rather than running f directly.