Why does this function handle not take the inputs?

So I have to approximate the value of sin(x) using the Runge-Kutta method. Here's my code:

function [X,Y]=rungekutta(fprime, timespan, y0, h) 
if ~exist('h','var') 
h=.1;
end

Y(1)=y0;
X(1)=timespan(1);

i=2;
while X(end)<timespan(end)
  X(i)=X(i-1) + h;
  k1 = h*fprime(X(i-1),Y(i-1));  
  k2 = h*fprime(X(i-1+h/2),Y(i-1)+k1/2);     
  k3 = h*fprime(X(i-1+h/2),Y(i-1)+k2/2);     
  k4 = h*fprime(X(i-1+h),Y(i-1)+k3);         
  Y(i) = Y(i-1) + (k1+2*k2+2*k3+k4)*h/6; % Approx soln
  i=i+1;
end

X=X';
Y=Y';
abs_err=mean(abs(Y-sin(X)));

plot(X,Y);
xlabel('Time(seconds)'); ylabel('Function Y');
title('Runge-Kutta Method');
hold on
plot(X,sin(X));
legend('Approximation','sin(x)');

display=fprintf('The absolute error is %f',abs_err);

When I type in the command window [X,Y]=rungekutta(@(X,Y)(cos(X,Y)), [0 10], sin(0), .5) using the my desired parameters, it gives me an error with cos saying "too many input arguments". Is this because I created the function handle within the input?

[Stephen23]

"Is this because I created the function handle within the input?"

No, where you create the function handle is totally unrelated to the fact that you call cos with the wrong number of inputs.

[Mohannad Abboushi]

Ok so when I call cos since it only depends on X is there a way to suppress that Y in the equations?

Answer 1

[Stephen23]

The problem has nothing to do with your function handle. It is (exactly as the error message states) solely because the way you call cos:

cos(X,Y)

does not make any sense: cos only has one input.

[Mohannad Abboushi]

Ok how about in this context?

https://www.mathworks.com/matlabcentral/answers/336867-can-someone-explain-to-me-whats-off-with-this-function-handle