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Can you help me please !

Asked by Johnny Vendetta on 3 Sep 2019
Latest activity Commented on by Johnny Vendetta on 7 Sep 2019
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.

  2 Comments

Adam
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.
thank you Adam

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1 Answer

Torsten
Answer by Torsten
on 3 Sep 2019
 Accepted Answer

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

  1 Comment

Thank you so much, Torsten.

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