MCQ
Given $f(x) = \int\limits_{ - 2}^x {t.g'(t)\,dt} $  for $x \geq  -2$, where $g$ is an increasing function, then 
  • A
    $ƒ(x)$ is an increasing function of $x$.
  • B
    $ƒ(x)$ is a decreasing function of $x.$
  • $ƒ(x)$ is increasing for $x > 0$ and decreasing for $x \in [-2,0)$.
  • D
    None of these

Answer

Correct option: C.
$ƒ(x)$ is increasing for $x > 0$ and decreasing for $x \in [-2,0)$.
c
$f^{\prime}(x)=x \cdot g^{\prime}(x)$

$\because g^{\prime}(x) \geq 0 \quad \forall x \geq-2$

$\therefore $  $f(\mathrm{x}) \downarrow$ for $[-2,0)$ and $\uparrow$ for $\mathrm{x}>0$

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