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← JEE Main 2026 · 4 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 16 of 75

JEE Main 2026 · 4 Apr · Shift 1, Mathematics question 16

If y=tan⁡−1(3cos⁡x−4sin⁡x4cos⁡x+3sin⁡x)+2tan⁡−1(x1+1−x2)y=\tan^{-1}\left(\dfrac{3\cos x-4\sin x}{4\cos x+3\sin x}\right)+2\tan^{-1}\left(\dfrac x{1+\sqrt{1-x^2}}\right), then dydx\dfrac{dy}{dx} at x=32x=\dfrac{\sqrt3}2 is equal to:

Choose one option
Answer and worked solution

Official answer: C

First term. 34−tan⁡x1+34tan⁡x=tan⁡(θ0−x)\dfrac{\frac34-\tan x}{1+\frac34\tan x}=\tan(\theta_0-x) with tan⁡θ0=34\tan\theta_0=\frac34, so the term is θ0−x\theta_0-x near x=32x=\frac{\sqrt3}2. Derivative −1-1.

Second term. With x=sin⁡ϕx=\sin\phi: sin⁡ϕ1+cos⁡ϕ=tan⁡ϕ2\dfrac{\sin\phi}{1+\cos\phi}=\tan\frac\phi2, so the term is ϕ=sin⁡−1x\phi=\sin^{-1}x. Derivative 11−x2=2\dfrac1{\sqrt{1-x^2}}=2 at x=32x=\frac{\sqrt3}2.

Total −1+2=1-1+2=1.

(C)