Question:
Let $f(x)=\sin ^{-1} x$ and $g(x)=\frac{x^{2}-x-2}{2 x^{2}-x-6}$. If $g(2)=\lim _{x \rightarrow 2} g(x)$, then the domain of the function fog is :
Correct Option: 1
Solution:
$g(2)=\lim _{x \rightarrow 2} \frac{(x-2)(x+1)}{(2 x+3)(x-2)}=\frac{3}{7}$
For domain of fog $(\mathrm{x})\left|\frac{x^{2}-x-2}{2 x^{2}-x-6}\right| \leq 1 \Rightarrow(x+1)^{2} \leq(2 x+3)^{2} \Rightarrow 3 x^{2}+10 x+8 \geq 0$
$\Rightarrow(3 x+4)(x+2) \geq 0$
$x \in(-\infty,-2] \cup\left(-\frac{4}{3}, \infty\right)$