The function $f(x) = \frac{x-2}{x+1}; x≠-1$ is increasing when (Where R is a set of real numbers) |
$x∈R$ $x∈R-\{-1\}$ $x∈R-\{1,-1\}$ $x∈R-\{0\}$ |
$x∈R-\{-1\}$ |
The correct answer is Option (2) → $x∈R-\{-1\}$ $f(x)=\frac{x-2}{x+1}$ $f'(x)=\frac{(x+1)\cdot1-(x-2)\cdot1}{(x+1)^2} =\frac{x+1-x+2}{(x+1)^2} =\frac{3}{(x+1)^2}$ Since $(x+1)^2>0$ for all real $x\neq -1$, $f'(x)=\frac{3}{(x+1)^2}>0$ for all $x\neq -1$. Therefore, the function is increasing for all real numbers except $x=-1$. The function is increasing on: $\;R-\{-1\}$. |