Find the domain of the function $f(x)=\sqrt{\sqrt{x^2-16}-3}$.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Find the domain of the function $f(x)=\sqrt{\sqrt{x^2-16}-3}$.
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
(-\infty,-5]\cup[5,\infty)
Find the domain of the function $f(x)=\sqrt{\sqrt{x^2-16}-3}$.
train