Skip to main content
Back to Inverse Trigonometric Functions
JEE Main 2024
Inverse Trigonometric Functions
Inverse Trigonometric Functions
Medium

Question

50tan(3tan1(12)+2cos1(15))+42tan(12tan1(22))50\tan \left( {3{{\tan }^{ - 1}}\left( {{1 \over 2}} \right) + 2{{\cos }^{ - 1}}\left( {{1 \over {\sqrt 5 }}} \right)} \right) + 4\sqrt 2 \tan \left( {{1 \over 2}{{\tan }^{ - 1}}(2\sqrt 2 )} \right) is equal to ____________.

Answer: 50

Solution

50tan(tan112+2tan1(12)+2tan1(2))50 \tan \left(\tan ^{-1} \frac{1}{2}+2 \tan ^{-1}\left(\frac{1}{2}\right)+2 \tan ^{-1}(2)\right) +42tan(tan12(22))+4 \sqrt{2} \tan \left(\frac{\tan ^{-1}}{2}(2 \sqrt{2})\right) 50tan(π+tan1(12))+42tan(12tan122)\Rightarrow 50 \tan \left(\pi+\tan ^{-1}\left(\frac{1}{2}\right)\right)+4 \sqrt{2} \tan \left(\frac{1}{2} \tan ^{-1} 2 \sqrt{2}\right) 50(12)+42tanα\Rightarrow \quad 50\left(\frac{1}{2}\right)+4 \sqrt{2} \tan \alpha Where 2α=tan1222 \alpha=\tan ^{-1} 2 \sqrt{2} 2tanα1tan2α=22\Rightarrow \frac{2 \tan \alpha}{1-\tan ^{2} \alpha}=2 \sqrt{2} \quad.. (i) 22tan2α+2tanα22=0\Rightarrow \quad 2 \sqrt{2} \tan ^{2} \alpha+2 \tan \alpha-2 \sqrt{2}=0 22tan2α+4tanα2tanα22=0\Rightarrow \quad 2 \sqrt{2} \tan ^{2} \alpha+4 \tan \alpha-2 \tan \alpha-2 \sqrt{2}=0 (22tanα2)(tanα2)=0\Rightarrow(2 \sqrt{2} \tan \alpha-2)(\tan \alpha-\sqrt{2})=0 tanα=2\Rightarrow \tan \alpha=\sqrt{2} or 12\frac{1}{\sqrt{2}} tanα=12\Rightarrow \tan \alpha=\frac{1}{\sqrt{2}} (tanα=2(\tan \alpha=\sqrt{2} doesn't satisfy (i)) 25+4212=29\Rightarrow \quad 25+4 \sqrt{2} \frac{1}{\sqrt{2}}=29

Practice More Inverse Trigonometric Functions Questions

View All Questions