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← JEE Main 2026 · 5 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 18 of 75

JEE Main 2026 · 5 Apr · Shift 1, Mathematics question 18

The value of the integral ∫0∞log⁡e(x)x2+4 dx\displaystyle\int_0^\infty\frac{\log_e(x)}{x^2+4}\,dx is:

Choose one option
Answer and worked solution

Official answer: B

Substitute x=4/tx=4/t. dx=−4 dt/t2dx=-4\,dt/t^2, and
I=∫0∞ln⁡4−ln⁡tt2+4 dt=ln⁡4∫0∞dtt2+4−I.I=\int_0^\infty\frac{\ln4-\ln t}{t^2+4}\,dt=\ln4\int_0^\infty\frac{dt}{t^2+4}-I.

So 2I=ln⁡4⋅π42I=\ln4\cdot\dfrac\pi4, giving I=πln⁡24I=\dfrac{\pi\ln2}4.

(B)