Answer
The function is continuous on the interval $[-3,3]$
Work Step by Step
The function is continuous on the interval because it meets two requirements:
1. $ \lim\limits_{x \to -3^+} 3-\sqrt {9-t^2} = 3 $ and
2. $ \lim\limits_{x \to 3^-} 3-\sqrt {9-t^2} = 3 $
on the closed interval $[-3,3]$
