draw two 3D curve but can't hold them in one figure

the first curve is a solution of a differential equation

      function dy=eq3(t,y)
      dy=zeros(3,1);
      dy(1)=-680*(y(1)-100000)/sqrt((y(1)-100000)^2+(y(2)-340*t)^2+(y(3)-10000)^2);
      dy(2)=-680*(y(2)-340*t)/sqrt((y(1)-100000)^2+(y(2)-340*t)^2+(y(3)-10000)^2);
      dy(3)=-680*(y(3)-10000)/sqrt((y(1)-100000)^2+(y(2)-340*t)^2+(y(3)-10000)^2);
      end
and the second one is a line in a 3Dspace

     [t,y]=ode45('eq3',[0:0.01:202],[0,0,0]);
     plot3(y(:,1),y(:,2),y(:,3))
     grid on
     hold on

     T=0:0.5:200;
     X=100000;
     Y=340*T;
     Z=10000;
     plot3(X,Y,Z,'r')
     xlabel('x轴')
     ylabel('y轴')
     zlabel('z轴')

but they don't show up together

Answer 1

[Aniruddha Katre]

The reason why the second plot does not show up is because the variables "X" and "Z" are both scalars while "Y" is a vector. You can just convert "X" and "Z" to vectors of the same dimensions as "Y" and the plot should work. Assuming you want to keep "X" and "Z" constant, you can convert them to vectors in the following manner:

X=100000*ones(length(T),1);
Z=10000*ones(length(T),1);

[Gary]

thx a lot

[Image Analyst]

You can "thank" him by officially "Accepting" his answer. It will give him reputation points.