If...end statement for taylor series expansion code

this is my function m file, but I cant seem to get it to work. the code runs but the value of mycos1(.5,100) is not equal to cos(.5), for instance. cant seem to find where the mistake is...

   function [cosx] = mycos1(x,n)
  %evaluates and sums the first n terms of the Taylor series
  %   use the for loop control structure to express the infinite taylor
  %   series

if n<=0
     error('n must be positive')
end

if rem(n,1)~=0
    error('n must be an integer')
end

cosx=1;
i=0;
for i=1:n+1
    cosx=cosx+(((-1)^i + x^(2*i))/factorial(2*i));
end
end

Answer 1

[John D'Errico]

I'm just wondering why you put a return statement as the very first executable line of code? Is it possible this is the problem? What happens when matlab hits that return?

[Zelda Luxenburry]

when I delete the "return", the error reads "line 7 error, not enough input arguments"...what would be a better way to say "if n is nonpositive or not an integer, display error" ?