Math Problem Statement

Evaluate the integral \( \int \frac{2x}{(x - 1)^2} \, dx \).

Solution

To solve the integral:

2x(x1)2dx\int \frac{2x}{(x - 1)^2} \, dx

we can proceed by using substitution.

  1. Choose a substitution: Let u=x1u = x - 1. Then, du=dxdu = dx and x=u+1x = u + 1.

  2. Rewrite the integrand in terms of uu: Substituting x=u+1x = u + 1 into the integrand: 2x(x1)2=2(u+1)u2.\frac{2x}{(x - 1)^2} = \frac{2(u + 1)}{u^2}.

    So, the integral becomes: 2(u+1)u2du.\int \frac{2(u + 1)}{u^2} \, du.

  3. Simplify the expression: Split the fraction: 2(u+1)u2du=(2uu2+2u2)du=(2u+2u2)du.\int \frac{2(u + 1)}{u^2} \, du = \int \left( \frac{2u}{u^2} + \frac{2}{u^2} \right) \, du = \int \left( \frac{2}{u} + \frac{2}{u^2} \right) \, du.

  4. Integrate each term: Now integrate term-by-term: 2udu+2u2du.\int \frac{2}{u} \, du + \int \frac{2}{u^2} \, du.

    • The first term, 2udu\int \frac{2}{u} \, du, integrates to 2lnu2 \ln |u|.
    • The second term, 2u2du\int \frac{2}{u^2} \, du, integrates to 2u-\frac{2}{u}.

    So, we get: 2lnu2u.2 \ln |u| - \frac{2}{u}.

  5. Substitute back u=x1u = x - 1: Replacing uu with x1x - 1, the result is: 2lnx12x1+C,2 \ln |x - 1| - \frac{2}{x - 1} + C, where CC is the constant of integration.

Final Answer:

2x(x1)2dx=2lnx12x1+C.\int \frac{2x}{(x - 1)^2} \, dx = 2 \ln |x - 1| - \frac{2}{x - 1} + C.

Would you like a deeper explanation on any step, or have any questions?


Here are 5 related questions you might find helpful:

  1. How would you approach this integral if the power in the denominator were different?
  2. What other techniques could we use to solve integrals with similar fractions?
  3. How does substitution simplify complex rational functions?
  4. How would the solution change if the numerator were x2x^2 instead of 2x2x?
  5. How can you verify the answer by differentiating the result?

Tip: When integrating rational functions, consider substitution if you see an expression and its derivative (or close to it) in the integrand.

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Math Problem Analysis

Mathematical Concepts

Integration
Substitution Method
Rational Functions

Formulas

Substitution: \( u = x - 1 \)
Integration of \( \frac{1}{u} \) and \( \frac{1}{u^2} \)

Theorems

Integration by Substitution

Suitable Grade Level

Grades 11-12