Math Problem Statement

solve this:

Solve the integral \( \int \frac{x}{2x^2 - 3x + 1} dx \).

Solution

We are tasked with solving the integral:

x2x23x+1dx\int \frac{x}{2x^2 - 3x + 1} \, dx

Steps to Solve:

  1. Simplify the denominator if possible: The denominator 2x23x+12x^2 - 3x + 1 is a quadratic expression, and we should check if it can be factored.

    Factoring 2x23x+12x^2 - 3x + 1: 2x23x+1=(2x1)(x1)2x^2 - 3x + 1 = (2x - 1)(x - 1)

    Thus, the integral becomes: x(2x1)(x1)dx\int \frac{x}{(2x - 1)(x - 1)} \, dx

  2. Use partial fraction decomposition: Express the fraction as a sum of simpler fractions: x(2x1)(x1)=A2x1+Bx1\frac{x}{(2x - 1)(x - 1)} = \frac{A}{2x - 1} + \frac{B}{x - 1} Multiply through by the denominator to find AA and BB: x=A(x1)+B(2x1)x = A(x - 1) + B(2x - 1) Expanding: x=A(x)A+B(2x)Bx = A(x) - A + B(2x) - B x=(A+2B)xABx = (A + 2B)x - A - B Comparing coefficients of xx and the constant term:

    • Coefficient of xx: A+2B=1A + 2B = 1
    • Constant term: AB=0-A - B = 0

    Solve the system of equations:

    1. A+2B=1A + 2B = 1
    2. AB=0-A - B = 0 (or A=BA = -B)

    Substituting A=BA = -B into A+2B=1A + 2B = 1: B+2B=1    B=1-B + 2B = 1 \implies B = 1 A=1A = -1

    Thus: x(2x1)(x1)=12x1+1x1\frac{x}{(2x - 1)(x - 1)} = \frac{-1}{2x - 1} + \frac{1}{x - 1}

  3. Integrate each term: x(2x1)(x1)dx=12x1dx+1x1dx\int \frac{x}{(2x - 1)(x - 1)} \, dx = \int \frac{-1}{2x - 1} \, dx + \int \frac{1}{x - 1} \, dx

    • First term: 12x1dx=12ln2x1\int \frac{-1}{2x - 1} \, dx = -\frac{1}{2} \ln|2x - 1|

    • Second term: 1x1dx=lnx1\int \frac{1}{x - 1} \, dx = \ln|x - 1|

  4. Combine results: x2x23x+1dx=12ln2x1+lnx1+C\int \frac{x}{2x^2 - 3x + 1} \, dx = -\frac{1}{2} \ln|2x - 1| + \ln|x - 1| + C

Final Answer:

12ln2x1+lnx1+C\boxed{-\frac{1}{2} \ln|2x - 1| + \ln|x - 1| + C}

Would you like me to explain a specific step in more detail?


Related Questions:

  1. How is partial fraction decomposition used in integration problems?
  2. What happens if the denominator is not factorable?
  3. Can this integral be solved using substitution instead of partial fractions?
  4. How do you handle definite integrals with logarithmic terms?
  5. How does the constant of integration affect the solution?

Tip:

Always check whether the denominator can be factored before jumping into other techniques; factoring often simplifies the problem significantly.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Integration
Partial Fraction Decomposition
Logarithmic Integration

Formulas

\( \int \frac{1}{ax + b} dx = \frac{1}{a} \ln|ax + b| + C \)

Theorems

Partial Fraction Decomposition
Logarithmic Integration Theorem

Suitable Grade Level

Undergraduate Calculus (Grades 11-12 or College)