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QJEEM22Mabac5: JEE Main 2022 Mathematics - Class 12 JEEM22Mabac5 Solution: If , then

If y = {\tan ^{ - 1}}\left( {\sec {x^3} - \tan {x^3}} \right),{\pi \over 2} < {x^3} < {{3\pi } \over 2} , then

Multiple Choice Options

  • A xy′′+2y′=0xy'' + 2y' = 0
  • B x2y′′−6y+3π2=0{x^2}y'' - 6y + {{3\pi } \over 2} = 0
  • C x2y′′−6y+3π=0{x^2}y'' - 6y + 3\pi = 0
  • D xy′′−4y′=0xy'' - 4y' = 0

Step-by-Step Verified Solution

Let x3=θ⇒θ2∈(π4, 3π4){x^3} = \theta \Rightarrow {\theta \over 2} \in \left( {{\pi \over 4},\,{{3\pi } \over 4}} \right)

∴\therefore y=tan⁡−1(sec⁡θ−tan⁡θ)y = {\tan ^{ - 1}}(\sec \theta - \tan \theta )

=tan⁡−1(1−sin⁡θcos⁡θ)= {\tan ^{ - 1}}\left( {{{1 - \sin \theta } \over {\cos \theta }}} \right)

∴\therefore y=π4−θ2y = {\pi \over 4} - {\theta \over 2}

y=π4−x32y = {\pi \over 4} - {{{x^3}} \over 2}

∴\therefore y′=−3x22y' = {{ - 3{x^2}} \over 2}

y′′=−3xy'' = - 3x

∴\therefore x2y′′−6y+3π2=0{x^2}y'' - 6y + {{3\pi } \over 2} = 0

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