how do we make vector the same length ( i get the error: vector must be the same length)

x=linspace(0,100);
y=linspace(0,100);
z=(-8.*x)/(x.^2+ y.^2 +1);
plot3(x,y,z)

Answer 1

[the cyclist]

I think you intended elementwise division. See the documentation for array vs. matrix operations.

x=linspace(0,100);
y=linspace(0,100);
z=(-8.*x)./(x.^2+ y.^2 +1); % Note that I changed this to ./
plot3(x,y,z)