# ∫ X 2 + X + 1 X 2 − X + 1 D X - Mathematics

Sum
$\int\frac{x^2 + x + 1}{x^2 - x + 1} \text{ dx }$

#### Solution

$Let I = \int\left( \frac{x^2 + x + 1}{x^2 - x + 1} \right)dx$
$\text{ Now },$

$\text{ Therefore },$
$\frac{x^2 + x + 1}{x^2 - x + 1} = 1 + \frac{2x}{x^2 - x + 1}$
$\Rightarrow \int\left( \frac{x^2 + x + 1}{x^2 - x + 1} \right) dx = \int dx + \int\left( \frac{2x - 1 + 1}{x^2 - x + 1} \right) dx$
$= \int dx + \int\left( \frac{2x - 1}{x^2 - x + 1} \right) dx + \int\frac{dx}{x^2 - x + 1}$
$= \int dx + \int\frac{\left( 2x - 1 \right) dx}{x^2 - x + 1} + \int\frac{dx}{x^2 - x + \left( \frac{1}{2} \right)^2 - \left( \frac{1}{2} \right)^2 + 1}$
$= \int dx + \int\frac{\left( 2x - 1 \right) dx}{x^2 - x + 1} + \int\frac{dx}{\left( x - \frac{1}{2} \right)^2 + \left( \frac{\sqrt{3}}{2} \right)^2}$
$= x + \text{ log } \left| x^2 - x + 1 \right| + \frac{2}{\sqrt{3}} \text{ tan }^{- 1} \left( \frac{2x - 1}{\sqrt{3}} \right) + C$

Concept: Indefinite Integral Problems
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#### APPEARS IN

RD Sharma Class 12 Maths
Chapter 19 Indefinite Integrals
Exercise 19.2 | Q 6 | Page 106