MCQ
$\int_{}^{} {\frac{1}{{{{({e^x} + {e^{ - x}})}^2}}}\;dx = } $
  • $ - \frac{1}{{2({e^{2x}} + 1)}} + c$
  • B
    $\frac{1}{{2({e^{2x}} + 1)}} + c$
  • C
    $ - \frac{1}{{{e^{2x}} + 1}}$
  • D
    None of these

Answer

Correct option: A.
$ - \frac{1}{{2({e^{2x}} + 1)}} + c$
a
(a)$\int_{}^{} {\frac{1}{{{{({e^x} + {e^{ - x}})}^2}}}\,dx = \int_{}^{} {\frac{{{e^{2x}}}}{{{{({e^{2x}} + 1)}^2}}}} \,dx} $
Put ${e^{2x}} + 1 = t \Rightarrow 2{e^{2x}}dx = dt,$ then it reduces to
$\frac{1}{2}\int_{}^{} {\frac{1}{{{t^2}}}dt} = - \frac{1}{2}.\frac{1}{t} + c = - \frac{1}{{2({e^{2x}} + 1)}} + c.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free