Verified Solution • 2025–26 Session moderate

QJEEM20Maf083: JEE Main 2020 Mathematics - Class 12 JEEM20Maf083 Solution: The integral is equal to (where C is a constant of integration):

The integral ∫(xxsin⁡x+cos⁡x)2dx\int {{{\left( {{x \over {x\sin x + \cos x}}} \right)}^2}dx} is equal to
(where C is a constant of integration):

Multiple Choice Options

  • A sec⁡x−xtan⁡xxsin⁡x+cos⁡x+C\sec x - {{x\tan x} \over {x\sin x + \cos x}} + C
  • B sec⁡x+xtan⁡xxsin⁡x+cos⁡x+C\sec x + {{x\tan x} \over {x\sin x + \cos x}} + C
  • C tan⁡x−xsec⁡xxsin⁡x+cos⁡x+C\tan x - {{x\sec x} \over {x\sin x + \cos x}} + C
  • D tan⁡x+xsec⁡xxsin⁡x+cos⁡x+C\tan x + {{x\sec x} \over {x\sin x + \cos x}} + C

Step-by-Step Verified Solution

∫(xxsin⁡x+cos⁡x)2dx{\int {\left( {{x \over {x\sin x + \cos x}}} \right)} ^2}dx

=∫(xcos⁡x).xcos⁡x dx(xsin⁡x+cos⁡x)2= \int {\left( {{x \over {\cos x}}} \right).{{x\cos x\,dx} \over {{{(x\sin x + \cos x)}^2}}}}

= xcos⁡x(−1xsin⁡x+cos⁡x)+∫(cos⁡x+xsin⁡xcos⁡2x)(1xsin⁡x+cos⁡x)dx{x \over {\cos x}}\left( { - {1 \over {x\sin x + \cos x}}} \right) + \int {\left( {{{\cos x + x\sin x} \over {{{\cos }^2}x}}} \right)} \left( {{1 \over {x\sin x + \cos x}}} \right)dx

=−xsec⁡xxsin⁡x+cos⁡x+∫sec⁡2x dx= - {{x\sec x} \over {x\sin x + \cos x}} + \int {{{\sec }^2}x\,dx}

=−xsec⁡xxsin⁡x+cos⁡x+tan⁡x+C= - {{x\sec x} \over {x\sin x + \cos x}} + \tan x + C

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