function fval = pendulum_fun(t,y)
%
% Evaluates f(t,y) for the pendulum problem 
%
%       theta'' + sin(theta) = 0
%
% The inputs are 
%   t = current time 
%   y = current position-velocity vector 
%

fval(1,1) = y(2,1);
fval(2,1) = -sin(y(1,1)); 

