Skip to main contentSkip to solution

If ∫0π/2tan⁡x dx=λ2\int_0^{\pi/2} \sqrt{\tan x} \, dx = \frac{\lambda}{\sqrt{2}}, then the value of λ\lambda is

Solution

✅ Correct Option: 1

Let I=∫0π/2tan⁡x dxI = \int_0^{\pi/2} \sqrt{\tan x}\, dx. By the property ∫0af(x)dx=∫0af(a−x)dx\int_0^a f(x)dx = \int_0^a f(a-x)dx: I=∫0π/2cot⁡x dxI = \int_0^{\pi/2} \sqrt{\cot x}\, dx. Adding: 2I=∫0π/2sin⁡x+cos⁡xsin⁡xcos⁡xdx2I = \int_0^{\pi/2} \frac{\sin x + \cos x}{\sqrt{\sin x \cos x}} dx. Substituting t=sin⁡x−cos⁡xt = \sin x - \cos x, dt=(cos⁡x+sin⁡x)dxdt = (\cos x + \sin x)dx: 2I=2∫−11dt1−t2=2 π2I = \sqrt{2}\int_{-1}^{1} \frac{dt}{\sqrt{1-t^2}} = \sqrt{2}\,\pi. So I=π/2I = \pi/\sqrt{2}, giving λ=π\lambda = \pi.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question