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Definite integral of sec x from 0 to pi over 6

Question

Compute ∫0π/6sec⁡x dx\displaystyle\int_0^{\pi/6}\sec x\,dx.

Short answer

12ln⁡3≈0.549\tfrac12\ln3\approx0.549. An antiderivative is ln⁡∣sec⁡x+tan⁡x∣\ln|\sec x+\tan x|. At π/6\pi/6 this is ln⁡ ⁣(23+13)=ln⁡3\ln\!\left(\tfrac{2}{\sqrt3}+\tfrac{1}{\sqrt3}\right)=\ln\sqrt3, and at 00 it is ln⁡1=0\ln1=0.

Adapted from Zhou, A Practical Guide to Quantitative Finance Interviews, sec. 3.2 Integration, 'Basics of integration B', p.36; question and answer rewritten by SelfMadeQuant.com.

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