\(\displaystyle Now, \ unless \ stated \ otherwise, \ we \ consider \ the \ domain \ of \ the \ vector-valued \ function\)
\(\displaystyle r \ to \ be \ the \ intersection \ of \ the \ domain \ of \ the \ component \ functions \ f, \ g, \ and \ h.\)
\(\displaystyle Hence, \ r(t) \ = \ 3ti-\sqrt{1-t^2}j+4k.\)
\(\displaystyle f(t) \ = \ 3t, \ domain \ = \ all \ reals.\)
\(\displaystyle g(t) \ = \ -\sqrt{1-t^2}, \ domain \ = \ [-1,1].\)
\(\displaystyle h(t) \ = \ 4, \ domain \ = \ all \ reals.\)
\(\displaystyle Therefore, \ the \ domain \ of \ r(t) \ = \ [-1,1].\)
\(\displaystyle What \ is \ the \ range \ of \ r(t)?\)