ode45 projectile motion with drag in Y direction. help im desperate

tspan = [0:.001:3];
IC = [0,0]; 
[t,y] = ode45(@f,tspan,IC);
ydot = y(:,1);
ydub = y(:,2);
    v0x = 10./sqrt(2); 
    x0 = 0;
    y0 = 0;
    x = x0 + v0x.*tspan + 0;
figure(1);hold on;axis on;
plot(x,y);
legend('ydot','ydub')
title('Projectile Motion')
xlabel('X-Position')
ylabel('Y-Position')
function ydub = f(t,y); 
    % [y] = [y(1), y(2)] = [y1, y2] = [ydot, ydub]
    c = 0;
    p = 0;
    m = 1;
    g = 9.8;
    ydub = [y(2); (c.*(y(1).^p))./m - g];
end

I am trying to graph the position of a projectile with drag in the Y direction, but not in the X direction, in 2D on the x-y plane, using ODE45 to find the position equation. The equation of motion I obtained is Ydoubledot = (((C)*Ydot^p)/m) - g. My graph does not look right, I think it is supposed to go up then down. Attached are pics of the problem statement, and the graph I am getting. Help im dying. Thanks.

[Torsten]

http://demonstrations.wolfram.com/ProjectileWithAirDrag/

Answer 1

[darova]

function temp
tspan = 0:.001:1;
x0 = 0;
y0 = 0;
a = 45;
v0x = 10*cosd(a);
v0y = 10*sind(a);
u0 = [x0 y0 v0x v0y];
[t,y] = ode45(@f,tspan,u0);
X = y(:,1);
Y = y(:,2);
% vx = y(:,3);
% vy = y(:,4);
plot(X,Y)
axis equal
legend('Trajectory');
title('Projectile Motion')
xlabel('X-Position')
ylabel('Y-Position')
end

function ydot = f(t,u)
    c = 0.5;
    p = 2;
    m = 1;
    g = 9.8;
%  	u(1);                       % x
%   u(2);                       % y
    ydot(1,1) = u(3);           % vx
    ydot(2,1) = u(4);           % vy
    ydot(3,1) = -c/m*u(3).^p;    % ax
    ydot(4,1) = -c/m*u(4).^p -g; % ay
end