1.
The domain of the function
f(x)=sin⁡−1(∣x∣+5x2+1)f(x)=\sin^{-1}\left(\frac{|x|+5}{x^2+1}\right)
is (−∞,−a]∪[a,∞)(-\infty,-a]\cup[a,\infty), then aa is equal to: