Math Problem Statement

Solution

The integral to solve is:

5x+7x2+4x+4dx\int \frac{5x + 7}{x^2 + 4x + 4} \, dx

Solution:

We can solve this integral using the method of completing the square and then applying a substitution.

  1. Complete the square for the quadratic expression in the denominator:

    x2+4x+4=(x+2)2x^2 + 4x + 4 = (x + 2)^2

    So the integral becomes:

    5x+7(x+2)2dx\int \frac{5x + 7}{(x + 2)^2} \, dx

  2. Substitute u=x+2u = x + 2, hence du=dxdu = dx and x=u2x = u - 2.

    Substituting into the integral:

    5(u2)+7u2du\int \frac{5(u - 2) + 7}{u^2} \, du

    Simplify the numerator:

    5u10+7u2du=5u3u2du\int \frac{5u - 10 + 7}{u^2} \, du = \int \frac{5u - 3}{u^2} \, du

    Break this into two integrals:

    5uu2du3u2du\int \frac{5u}{u^2} \, du - \int \frac{3}{u^2} \, du

    Simplify each term:

    5udu3u2du\int \frac{5}{u} \, du - \int 3u^{-2} \, du

  3. Integrate each term:

    • The first term: 5udu=5lnu\int \frac{5}{u} \, du = 5 \ln|u|
    • The second term: 3u2du=3(u1)=3u\int 3u^{-2} \, du = 3 \cdot \left(-u^{-1}\right) = -\frac{3}{u}

    So the integral becomes:

    5lnu+3u+C5 \ln|u| + \frac{3}{u} + C

  4. Substitute back u=x+2u = x + 2:

    5lnx+2+3x+2+C5 \ln|x + 2| + \frac{3}{x + 2} + C

Thus, the final answer is:

5x+7x2+4x+4dx=5lnx+2+3x+2+C\int \frac{5x + 7}{x^2 + 4x + 4} \, dx = 5 \ln|x + 2| + \frac{3}{x + 2} + C

Would you like further details or have any questions?

Here are some related questions for further practice:

  1. How would you solve 3x+5x2+6x+9dx\int \frac{3x + 5}{x^2 + 6x + 9} \, dx?
  2. What is the integral of 7x+4x2+2x+1dx\int \frac{7x + 4}{x^2 + 2x + 1} \, dx?
  3. How do you complete the square for the expression x2+6x+9x^2 + 6x + 9?
  4. What method would you use to solve 2x+3x2+4dx\int \frac{2x + 3}{x^2 + 4} \, dx?
  5. How does substitution help in solving complex integrals?

Tip: When dealing with rational functions, consider using substitution and completing the square to simplify the integrals.

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Math Problem Analysis

Mathematical Concepts

Integration
Rational Functions
Completing the Square
Substitution

Formulas

Integration by Substitution

Theorems

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Suitable Grade Level

Advanced High School