MCQ
$\int_{}^{} {\frac{{dx}}{{{e^{ - 2x}}{{({e^{2x}} + 1)}^2}}} = } $
  • $\frac{{ - 1}}{{2({e^{2x}} + 1)}} + c$
  • B
    $\frac{1}{{2({e^{2x}} + 1)}} + c$
  • C
    $\frac{1}{{{e^{2x}} + 1}} + c$
  • D
    $\frac{{ - 1}}{{{e^{2x}} + 1}} + c$

Answer

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

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