MCQ
If $\int_{}^{} {f(x)\,dx} = x{e^{ - \log |x|}} + f(x),$ then $f(x)$ is
  • A
    $1$
  • B
    $0$
  • $c{e^x}$
  • D
    $\log x$

Answer

Correct option: C.
$c{e^x}$
c
(c) $\int_{}^{} {f(x)dx = x{e^{\log \left| {\frac{1}{x}} \right|}} + f(x) \Rightarrow \int_{}^{} {f(x)dx = \frac{x}{{|x|}} + f(x)} } $

On differentiating both sides , we get $f(x) = 0 + f'(x)$

We know $\frac{d}{{dx}}({e^x}) = {e^x},\,\,$

$\therefore \,\,f(x) = c{e^x}$.

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