i want to draw a triangle with vertices on 3 axis, how to do it? and also how to draw a incircle in it?

lets say the vertices are (1,0,0), (0,1,0), (0,0,1)

Answer 1

[Cris LaPierre]

You could just use plot3. Just remember to close the loop.

plot3([1,0,0,1], [0,1,0,0], [0,0,1,0])

If you want it filled in, you could use fill3.

figure
fill3([1,0,0], [0,1,0], [0,0,1],'m')

[abu sharique shamshad khan]

and how can i make an incircle in it

[Cris LaPierre]

Same process. You just need a lot more points to make the shape look circular.

In 2D, you could use the rectangle function. See this example.