The function \(f(x) = \displaystyle\frac{x - 2}{x + 1}\), \(x \ne -1\), is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → strictly increasing in \((-\infty, -1)\) and strictly increasing in \((-1, \infty)\)
By the quotient rule:
\( \displaystyle f'(x) = \frac{(x + 1) - (x - 2)}{(x + 1)^{2}} \)
\( \displaystyle = \frac{3}{(x + 1)^{2}} \)
The square \((x + 1)^{2}\) is positive for every x ≠ −1, so \(f'(x) \gt 0\) on both sides of x = −1.
So f is strictly increasing in \((-\infty, -1)\) and also in \((-1, \infty)\).