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QJEEM22Ma70e8: JEE Main 2022 Mathematics - Class 12 JEEM22Ma70e8 Solution

 The integral ∫(1−13)(cos⁡x−sin⁡x)(1+23sin⁡2x)dx is equal to \text { The integral } \int \frac{\left(1-\frac{1}{\sqrt{3}}\right)(\cos x-\sin x)}{\left(1+\frac{2}{\sqrt{3}} \sin 2 x\right)} d x \text { is equal to }

Multiple Choice Options

  • A 12log⁡e∣tan⁡(x2+π12)tan⁡(x2+π6)∣+C\frac{1}{2} \log _{e}\left|\frac{\tan \left(\frac{x}{2}+\frac{\pi}{12}\right)}{\tan \left(\frac{x}{2}+\frac{\pi}{6}\right)}\right|+C
  • B 12log⁡e∣tan⁡(x2+π6)tan⁡(x2+π3)∣+C\frac{1}{2} \log _{e}\left|\frac{\tan \left(\frac{x}{2}+\frac{\pi}{6}\right)}{\tan \left(\frac{x}{2}+\frac{\pi}{3}\right)}\right|+C
  • C log⁡e∣tan⁡(x2+π6)tan⁡(x2+π12)∣+C\log _{e}\left|\frac{\tan \left(\frac{x}{2}+\frac{\pi}{6}\right)}{\tan \left(\frac{x}{2}+\frac{\pi}{12}\right)}\right|+C
  • D 12log⁡e∣tan⁡(x2−π12)tan⁡(x2−π6)∣+C\frac{1}{2} \log _{e}\left|\frac{\tan \left(\frac{x}{2}-\frac{\pi}{12}\right)}{\tan \left(\frac{x}{2}-\frac{\pi}{6}\right)}\right|+C

Step-by-Step Verified Solution

=∫(1−13)(cos⁡x−sin⁡x)(1+23sin⁡2x)dx= \int {{{\left( {1 - {1 \over {\sqrt 3 }}} \right)(\cos x - \sin x)} \over {\left( {1 + {2 \over {\sqrt 3 }}\sin 2x} \right)}}dx}

=∫(3−13)2sin⁡(π4−x)(23)(sin⁡π3+sin⁡2x)dx= \int {{{\left( {{{\sqrt 3 - 1} \over {\sqrt 3 }}} \right)\sqrt 2 \sin \left( {{\pi \over 4} - x} \right)} \over {\left( {{2 \over {\sqrt 3 }}} \right)\left( {\sin {\pi \over 3} + \sin 2x} \right)}}dx}

=∫(3−1)2sin⁡(π4−x)(sin⁡π3+sin⁡2x)dx= \int {{{{{(\sqrt 3 - 1)} \over {\sqrt 2 }}\sin \left( {{\pi \over 4} - x} \right)} \over {\left( {\sin {\pi \over 3} + \sin 2x} \right)}}dx}

=∫3−122sin⁡(π4−x)sin⁡(π6+x)cos⁡(π6−x)dx= \int {{{{{\sqrt 3 - 1} \over {2\sqrt 2 }}\sin \left( {{\pi \over 4} - x} \right)} \over {\sin \left( {{\pi \over 6} + x} \right)\cos \left( {{\pi \over 6} - x} \right)}}dx}

=12∫2sin⁡π12sin⁡(π4−x)sin⁡(π6+x)cos⁡(π6−x)dx= {1 \over 2}\int {{{2\sin {\pi \over {12}}\sin \left( {{\pi \over 4} - x} \right)} \over {\sin \left( {{\pi \over 6} + x} \right)\cos \left( {{\pi \over 6} - x} \right)}}dx}

=12∫cos⁡(π6−x)−cos⁡(π3−x)sin⁡(π6+x)cos⁡(π6−x)dx= {1 \over 2}\int {{{\cos \left( {{\pi \over 6} - x} \right) - \cos \left( {{\pi \over 3} - x} \right)} \over {\sin \left( {{\pi \over 6} + x} \right)\cos \left( {{\pi \over 6} - x} \right)}}dx}

=12[∫cosec(π6+x)dx−∫sec⁡(π6−x)dx]= {1 \over 2}\left[ {\int {{\mathop{\rm cosec}\nolimits} \left( {{\pi \over 6} + x} \right)dx - \int {\sec \left( {{\pi \over 6} - x} \right)dx} } } \right]

=12[ln⁡∣tan⁡(π12+x2)∣−∫cos⁡ec(π3−x)dx]= {1 \over 2}\left[ {\ln \left| {\tan \left( {{\pi \over {12}} + {x \over 2}} \right)} \right| - \int {\cos ec\left( {{\pi \over 3} - x} \right)dx} } \right]

=12[ln⁡∣tan⁡(π12+x2)∣−ln⁡∣π6+x2∣]+C= {1 \over 2}\left[ {\ln \left| {\tan \left( {{\pi \over {12}} + {x \over 2}} \right)} \right| - \ln \left| {{\pi \over 6} + {x \over 2}} \right|} \right] + C

=12ln⁡∣tan⁡(π2+x2)tan⁡(π6+x2)∣+C= {1 \over 2}\ln \left| {{{\tan \left( {{\pi \over 2} + {x \over 2}} \right)} \over {\tan \left( {{\pi \over 6} + {x \over 2}} \right)}}} \right| + C

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