What is the integral of ln(x^2+x+2) ?

The integral of ln(x^2+x+2) is xln(x^2+x+2)+1/2 ln(x^2+x+2)+sqrt(7)arctan(1/(sqrt(7))(2x+1))-2x-1+C

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

integral of ln(x^2+x+2)

\int ln (x^{2} + x + 2) d x

x ln (x^{2} + x + 2) + \frac{1}{2} ln (x^{2} + x + 2) + 7 arctan (\frac{1}{7} (2 x + 1)) - 2 x - 1 + C

Solution steps

\int ln (x^{2} + x + 2) d x

Complete the square

x^{2} + x + 2 : (x + \frac{1}{2})^{2} + \frac{7}{4}

= \int ln ((x + \frac{1}{2})^{2} + \frac{7}{4}) d x

Apply u-substitution

= \int ln (u^{2} + \frac{7}{4}) d u

Apply Integration By Parts

= u ln (u^{2} + \frac{7}{4}) - \int \frac{8 u ^{2}}{4 u ^{2} + 7} d u

\int \frac{8 u ^{2}}{4 u ^{2} + 7} d u = - 7 arctan (\frac{2}{7} u) + 2 u

= u ln (u^{2} + \frac{7}{4}) - (- 7 arctan (\frac{2}{7} u) + 2 u)

Substitute back

u = x + \frac{1}{2}

= (x + \frac{1}{2}) ln ((x + \frac{1}{2})^{2} + \frac{7}{4}) - (- 7 arctan (\frac{2}{7} (x + \frac{1}{2})) + 2 (x + \frac{1}{2}))

Simplify

(x + \frac{1}{2}) ln ((x + \frac{1}{2})^{2} + \frac{7}{4}) - (- 7 arctan (\frac{2}{7} (x + \frac{1}{2})) + 2 (x + \frac{1}{2})) : x ln (x^{2} + x + 2) + \frac{1}{2} ln (x^{2} + x + 2) + 7 arctan (\frac{1}{7} (2 x + 1)) - 2 x - 1

= x ln (x^{2} + x + 2) + \frac{1}{2} ln (x^{2} + x + 2) + 7 arctan (\frac{1}{7} (2 x + 1)) - 2 x - 1

Add a constant to the solution

= x ln (x^{2} + x + 2) + \frac{1}{2} ln (x^{2} + x + 2) + 7 arctan (\frac{1}{7} (2 x + 1)) - 2 x - 1 + C

What is the integral of ln(x^2+x+2) ?
The integral of ln(x^2+x+2) is xln(x^2+x+2)+1/2 ln(x^2+x+2)+sqrt(7)arctan(1/(sqrt(7))(2x+1))-2x-1+C