RK4 error for the code

Hi, I am integrating a differential equation using the code attached in the image.While i am executing my code i am getting the following error message,Can anyone help me with this.

??? Error using ==> feval

Argument must contain a string or function_handle.

Error in ==> rk4 at 21

k1 = h*feval(f,xo,u);

Answer 1

[Titus Edelhofer]

Hi,

the error tells you, that the first argument to call rk4 should be a function that can be called, so either the name as a string (of a .m file), or a function handle.

Titus

[deep]

Thank you Problem resolved :)