Math Problem Statement

Integrate x/(x+1)^2

Solution

To integrate the expression x(x+1)2dx\int \frac{x}{(x+1)^2} \, dx, we can use substitution and some simplification.

Solution:

  1. Substitute u=x+1u = x + 1, which implies that du=dxdu = dx and x=u1x = u - 1.

    This substitution changes the integral as follows: x(x+1)2dx=u1u2du\int \frac{x}{(x+1)^2} \, dx = \int \frac{u - 1}{u^2} \, du

  2. Simplify the integrand: =(uu21u2)du=(1u1u2)du= \int \left( \frac{u}{u^2} - \frac{1}{u^2} \right) \, du = \int \left( \frac{1}{u} - \frac{1}{u^2} \right) \, du

  3. Separate the integrals: =1udu1u2du= \int \frac{1}{u} \, du - \int \frac{1}{u^2} \, du

  4. Integrate each term:

    • For 1udu\int \frac{1}{u} \, du, the result is lnu\ln |u|.
    • For 1u2du\int \frac{1}{u^2} \, du, rewrite it as u2u^{-2}, and integrate to get 1u-\frac{1}{u}.

    So, 1udu1u2du=lnu+1u+C\int \frac{1}{u} \, du - \int \frac{1}{u^2} \, du = \ln |u| + \frac{1}{u} + C

  5. Substitute back u=x+1u = x + 1: =lnx+1+1x+1+C= \ln |x + 1| + \frac{1}{x + 1} + C

Final Answer:

x(x+1)2dx=lnx+1+1x+1+C\int \frac{x}{(x+1)^2} \, dx = \ln |x + 1| + \frac{1}{x + 1} + C

Would you like more details on any step, or have any questions?


Related Questions:

  1. How would you integrate x2(x+1)3dx\int \frac{x^2}{(x+1)^3} \, dx?
  2. Can you use a different method to integrate x(x+1)2dx\int \frac{x}{(x+1)^2} \, dx?
  3. What happens if we have 1(x+1)2dx\int \frac{1}{(x+1)^2} \, dx?
  4. How do you find the antiderivative of x(x+1)ndx\int \frac{x}{(x+1)^n} \, dx for an arbitrary nn?
  5. What is the integral of x+2(x+1)2dx\int \frac{x+2}{(x+1)^2} \, dx?

Tip:

When integrating rational functions, substitution is often helpful, especially when the derivative of the denominator closely resembles the numerator.

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Math Problem Analysis

Mathematical Concepts

Integration
Substitution Method
Simplification of Rational Functions

Formulas

Integral of 1/u: ∫(1/u) du = ln|u| + C
Integral of u^n: ∫u^n du = u^(n+1)/(n+1) + C, where n ≠ -1

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Undergraduate Calculus (Grades 11-12 and above)