Matlab won't plot my 3d graph

I entered

t= 0:0.4:40;

x=20.*sin(t);

y=20.*cos(t);

z= 10-(t./4).^2;

plot3(x,y,z)

and clicked run bit nothing happened?

Answer 1

[JESUS DAVID ARIZA ROYETH]

it work well

close all
figure
x=20.*sin(t);
y=20.*cos(t);
z= 10-(t./4).^2;
plot3(x,y,z)