Can you help me please !

Question

Johnny Vendetta 2019-9-3

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/478709-can-you-help-me-please

评论： Johnny Vendetta 2019-9-7

采纳的回答： Torsten

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 个评论
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Adam 2019-9-3

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 2019-9-7

thank you Adam

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Answer 1

Torsten 2019-9-3

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/478709-can-you-help-me-please#answer_390213

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