/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 22 Evaluate the integral. $$ \i... [FREE SOLUTION] | 91Ó°ÊÓ

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Evaluate the integral. $$ \int_{0}^{\pi / 2} \frac{\cos x}{1+\sin ^{2} x} d x $$

Short Answer

Expert verified
The value of the integral is \(\pi / 4\).

Step by step solution

01

Setting Up the Substitution

In attempt to simplify the integral, let's make a substitution. We substitute \(u = \sin x\) which implies \(du = \cos x \, dx\). Replacing \(\cos x \, dx\) with \(du\) makes the integral simpler. But we need to make sure to change the limits of integration as well. The initial lower limit was \(x = 0\) which now translates to \(u = \sin 0 = 0\), and the initial upper limit was \(x = \pi / 2\) which now translates to \(u = \sin (\pi / 2) = 1\).
02

Substitute Into the Integral

Now our integral, with the substitution and the new limits of integration, becomes: \(\int_{0}^{1} \frac{1}{1+u^2} du\). This is a simpler integral to calculate.
03

Evaluating the Integral

The integral \(\int \frac{1}{1+u^2} du\) is a standard integral whose result is \(\arctan(u)\). Applying this rule, we get \(\arctan(u)\) from 0 to 1.
04

Evaluating the Limits

The final step involves substituting the limits of integration back into the result, and subtracting to find the final answer: \(\arctan(1) - \arctan(0) = \pi/4 - 0 = \pi/4\).

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