MCQ
For which value of $x$ , the function $f(x) = {x^2} - 2x$ is decreasing
- A$x > 1$
- B$x > 2$
- ✓$x < 1$
- D$x < 2$
✓
Answer
Correct option: C.
$x < 1$
c
(c) $f(x) = {(x - 1)^2} - 1$. Hence decreasing in $ x < 1.$
(c) $f(x) = {(x - 1)^2} - 1$. Hence decreasing in $ x < 1.$
Aliter : $f'(x) = 2x - 2 = 2(x - 1)$
To be decreasing, $2(x - 1) < 0 \Rightarrow (x - 1) < 0 \Rightarrow x < 1$.
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