# Chapter 8 - Techniques of Integration - 8.2 Trigonometric Integrals - Exercises - Page 403: 53

$$\ln \left(1+\sqrt{2}\right)$$

#### Work Step by Step

\begin{align*} \int_{0}^{\pi/4}\frac{dx}{\cos x}&=\int_{0}^{\pi/4}\sec xdx\\ &=\ln |\sec x+\tan x|\bigg|_{0}^{\pi/4}\\ &= \ln \left(1+\sqrt{2}\right) \end{align*}

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.