JEE Main 2021 · 20 July · Evening Shift · Mathematics · Inverse Trigonometric Functions
B. 22021\dfrac{220}{21}21220
We have,
tan(2tan−1(35)+sin−1(513))\tan \left(2\tan^{- 1}\left(\dfrac{3}{5}\right) + \sin^{- 1}\left(\dfrac{5}{13}\right)\right)tan(2tan−1(53)+sin−1(135))
=tan(tan−1(35)+tan−1(35)+sin−1(513))= \tan \left(\tan^{- 1}\left(\dfrac{3}{5}\right) + \tan^{- 1}\left(\dfrac{3}{5}\right) + \sin^{- 1}\left(\dfrac{5}{13}\right)\right)=tan(tan−1(53)+tan−1(53)+sin−1(135))
=tan(tan−1(35+351−925)+sin−1(513))= \tan \left(\tan^{- 1}\left(\dfrac{\dfrac{3}{5} + \dfrac{3}{5}}{1 - \dfrac{9}{25}}\right) + \sin^{- 1}\left(\dfrac{5}{13}\right)\right)=tantan−11−25953+53+sin−1(135)
=tan(tan−1(158)+tan−1(512))= \tan \left(\tan^{- 1}\left(\dfrac{15}{8}\right) + \tan^{- 1}\left(\dfrac{5}{12}\right)\right)=tan(tan−1(815)+tan−1(125))
=tan−1[158+5121−158⋅512]=tan−122021= \tan^{- 1}\left[\dfrac{\dfrac{15}{8} + \dfrac{5}{12}}{1 - \dfrac{15}{8} \cdot \dfrac{5}{12}}\right] = \tan^{- 1}\dfrac{220}{21}=tan−11−815⋅125815+125=tan−121220
=tan(tan−122021)=22021= \tan \left(\tan^{- 1}\dfrac{220}{21}\right) = \dfrac{220}{21}=tan(tan−121220)=21220