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MHT CET · Maths · Definite Integration

\(\int_0^{\frac{\pi}{2}} \frac{\sin x}{1+\cos ^2 x} d x\) has the value

  1. A \(-\frac{\pi}{4}\)
  2. B \(\frac{\pi}{4}\)
  3. C \(\frac{\pi}{2}\)
  4. D \(0\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{\pi}{4}\)

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \int_0^{\pi / 2} \frac{\sin x}{1+\cos ^2 \mathrm{x}} \mathrm{dx}=-\int_1^0 \frac{\mathrm{dt}}{1+\mathrm{t}^2}[\text { let } \cos \mathrm{x}=\mathrm{t}] \\ & =-\left[\tan ^{-1} \mathrm{t}\right]_1^0 \\ & =-\left(0-\frac{\pi}{4}\right) \\ & =\frac{\pi}{4}\end{aligned}\)