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← JEE Main 2026 · 4 Apr · Shift 2
MathematicsSingle correct+4 / -1Question 20 of 75

JEE Main 2026 · 4 Apr · Shift 2, Mathematics question 20

The integral ∫01cot⁡−1(1+x+x2)dx\displaystyle\int_0^1\cot^{-1}\left(1+x+x^2\right)dx is equal to:

Choose one option
Answer and worked solution

Official answer: D

Split the integrand. cot⁡−1(1+x+x2)=tan⁡−1(x+1)−tan⁡−1x\cot^{-1}(1+x+x^2)=\tan^{-1}(x+1)-\tan^{-1}x.

Integrate. With F(t)=∫0ttan⁡−1=ttan⁡−1t−12ln⁡(1+t2)F(t)=\int_0^t\tan^{-1}=t\tan^{-1}t-\frac12\ln(1+t^2), the integral is F(2)−2F(1)F(2)-2F(1):
2tan⁡−12−12ln⁡5−π2+ln⁡2=2tan⁡−12−12ln⁡54−π2.2\tan^{-1}2-\tfrac12\ln5-\tfrac\pi2+\ln2=2\tan^{-1}2-\tfrac12\ln\tfrac54-\tfrac\pi2.

(D)