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← JEE Main 2022 · 29 Jun · Shift 1
MathematicsInteger+4 / -1Question 26 of 90

JEE Main 2022 · 29 Jun · Shift 1, Mathematics question 26

50tan⁡(3tan⁡−1(12)+2cos⁡−1(15))+42tan⁡(12tan⁡−1(22))50\tan\left(3\tan^{-1}\left(\dfrac12\right)+2\cos^{-1}\left(\dfrac1{\sqrt5}\right)\right)+4\sqrt2\tan\left(\dfrac12\tan^{-1}\left(2\sqrt2\right)\right) is equal to ______.

Answer and worked solution

Official answer: 29

First term. With tan⁡−112=a\tan^{-1}\frac12=a, cos⁡−115=tan⁡−12=π2−a\cos^{-1}\frac1{\sqrt5}=\tan^{-1}2=\frac\pi2-a, so the angle is π+a\pi+a and tan⁡=12\tan=\frac12: 50⋅12=2550\cdot\frac12=25.

Second term. tan⁡ϕ2\tan\frac\phi2 with tan⁡ϕ=22\tan\phi=2\sqrt2, cos⁡ϕ=13\cos\phi=\frac13: tan⁡ϕ2=12\tan\frac\phi2=\frac1{\sqrt2}, giving 42⋅12=44\sqrt2\cdot\frac1{\sqrt2}=4.

Total 29.

Answer: 29