Verified Solution • 2025–26 Session moderate

QJEEM22Maff85: JEE Main 2022 Mathematics - Class 12 JEEM22Maff85 Solution: Let . Then

Let I=∫π/4π/3(8sin⁡x−sin⁡2xx)dxI=\int_{\pi / 4}^{\pi / 3}\left(\frac{8 \sin x-\sin 2 x}{x}\right) d x . Then

Multiple Choice Options

  • A π2<I<3π4{\pi \over 2} < I < {{3\pi } \over 4}
  • B π5<I<5π12{\pi \over 5} < I < {{5\pi } \over {12}}
  • C 5π12<I<23π{{5\pi } \over {12}} < I < {{\sqrt 2 } \over 3}\pi
  • D 3π4<I<π{{3\pi } \over 4} < I < \pi

Step-by-Step Verified Solution

I comes out around 1.536 which is not satisfied by any given options.

\int\limits_{\pi /4}^{\pi /3} {{{8x - 2x} \over x}dx &gt; I &gt; \int\limits_{\pi /4}^{\pi /3} {{{8\sin x - 2x} \over x}dx} }

{\pi \over 2} &gt; I &gt; \int\limits_{\pi /4}^{\pi /3} {\left( {{{8\sin x} \over x} - 2} \right)dx}

sin⁡xx{{\sin x} \over x} is decreasing in (π4,π3)\left( {{\pi \over 4},{\pi \over 3}} \right) so it attains maximum at x=π4x = {\pi \over 4}

I &gt; \int\limits_{\pi /4}^{\pi /3} {\left( {{{8\sin x/3} \over {x/3}} - 2} \right)dx}

I &gt; \sqrt 3 - {\pi \over 6}

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