function [xdot] = sect_3_prob_2_part_d_J_ode_fn(t,x, alpha_0, alpha_1)
%   
% Written by:
% -- 
% John L. Weatherwax                2006-08-28
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

n = length(x); 
xdot = zeros(n,1); % x = [ v(t), gamma(t) ] 

v     = x(1); 
gamma = x(2); 

xdot(1) = ( 10000 * cos( alpha_0 + alpha_1 * t ) - 0.0004 * v^2 - 32*sin( gamma ) )/(20.-t);
xdot(2) = ( 10000 * sin( alpha_0 + alpha_1 * t ) - 32*cos( gamma ) )/((20.-t)*v);