What is the integral of (x+1)/(x^2+4x+5) ?

The integral of (x+1)/(x^2+4x+5) is 1/2 ln|x^2+4x+5|-arctan(x+2)+C

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

integral of (x+1)/(x^2+4x+5)

\int \frac{x + 1}{x ^{2} + 4 x + 5} d x

\frac{1}{2} ln x^{2} + 4 x + 5 - arctan (x + 2) + C

Solution steps

\int \frac{x + 1}{x ^{2} + 4 x + 5} d x

Complete the square

x^{2} + 4 x + 5 : (x + 2)^{2} + 1

= \int \frac{x + 1}{( x + 2 ) ^{2} + 1} d x

Apply u-substitution

= \int \frac{u - 1}{u ^{2} + 1} d u

Expand

\frac{u - 1}{u ^{2} + 1} : \frac{u}{u ^{2} + 1} - \frac{1}{u ^{2} + 1}

Apply the Sum Rule:

\int f (x) \pm g (x) d x = \int f (x) d x \pm \int g (x) d x

= \int \frac{u}{u ^{2} + 1} d u - \int \frac{1}{u ^{2} + 1} d u

\int \frac{u}{u ^{2} + 1} d u = \frac{1}{2} ln u^{2} + 1

\int \frac{1}{u ^{2} + 1} d u = arctan (u)

= \frac{1}{2} ln u^{2} + 1 - arctan (u)

Substitute back

u = x + 2

= \frac{1}{2} ln (x + 2)^{2} + 1 - arctan (x + 2)

Simplify

\frac{1}{2} ln (x + 2)^{2} + 1 - arctan (x + 2) : \frac{1}{2} ln x^{2} + 4 x + 5 - arctan (x + 2)

= \frac{1}{2} ln x^{2} + 4 x + 5 - arctan (x + 2)

Add a constant to the solution

= \frac{1}{2} ln x^{2} + 4 x + 5 - arctan (x + 2) + C

What is the integral of (x+1)/(x^2+4x+5) ?
The integral of (x+1)/(x^2+4x+5) is 1/2 ln|x^2+4x+5|-arctan(x+2)+C