How to solve 'vector must be the same length', 'functions behave unexpectedly' errors when graphing vector equation

The vector equation is

r(t) = <3, t, 2-t^2>

first of all . I tried

t=linspace(-10,10);

x=3;

y=t;

z=2-(t.^2);

plot3(x,y,z)

I got 'plot3 error' - vector must be the same lengths

Second, I tried

t=linspace(-10,10);

xt=@(t) 3;

yt=@(t) t;

zt=@(t) 2-(t.^2);

fplot3(xt,yt,zt)

I got warning function behaves unexpectedly on array inputs

how can I solve it? I really appreciate any help.

[Asad (Mehrzad) Khoddam]

the code

t=linspace(-10,10);

uses the default number of divisions.

You can use more division like this:

t=linspace(-10,10,51);
% or
t=linspace(-10,10,201);

Answer 1

[Asad (Mehrzad) Khoddam]

in the first code, instead of

x=3;

use this one:

x=3*ones(size(t));

[수정 이]

Thank you very much! I really appreciate your help!

[Asad (Mehrzad) Khoddam]

You are welcome