## Can you help me please !

### Johnny Vendetta (view profile)

on 3 Sep 2019
Latest activity Commented on by Johnny Vendetta

on 7 Sep 2019

### Torsten (view profile)

I run code Matlab:
function yp=khidonghoc(t,y)
m = 10;
cd = 0.2;
g = 9.81;
w = m*g;
tspan=[0 5];
y0=[0;100;0;10];
yp = zeros(4,1);
yp(1)= y(2);
yp(2) = ((-cd/m)*y(2)*(y(2)^2+y(4)^2)^(0.5));
yp(3) = y(4);
yp(4) = ((-w/m)-(cd/m)*y(4)*(y(2)^2+y(4)^2)^(0.5));
[t,y]=ode45('khidonghoc',tspan,y0);
plot(t,y(:,1),y(:,3))
hold on;grid on;
xlabel('X-Displacement')
ylabel('Y-Displacement')
title('X vs Y Displacement')
end
Matlab error: "Not enough input arguments.
Error in khidonghoc (line 9)
yp(1)= y(2);"
Thanks you very much.

on 3 Sep 2019
Pass in some arguments! How did you call the function? It expects two input arguments so if you don't pass them in it will give you that error.
Johnny Vendetta

on 7 Sep 2019

### Torsten (view profile)

on 3 Sep 2019

function main
tspan=[0 5];
y0=[0;100;0;10];
[t,y]=ode45(@khidonghoc,tspan,y0);
plot(t,y(:,1),t,y(:,3))
hold on;grid on;
xlabel('X-Displacement')
ylabel('Y-Displacement')
title('X vs Y Displacement')
end
function yp=khidonghoc(t,y)
m = 10;
cd = 0.2;
g = 9.81;
w = m*g;
yp = zeros(4,1);
yp(1)= y(2);
yp(2) = ((-cd/m)*y(2)*(y(2)^2+y(4)^2)^(0.5));
yp(3) = y(4);
yp(4) = ((-w/m)-(cd/m)*y(4)*(y(2)^2+y(4)^2)^(0.5));
end

Johnny Vendetta

### Johnny Vendetta (view profile)

on 3 Sep 2019
Thank you so much, Torsten.