Math Problem Statement

Consider the integral: ∫(ln(9x)/x^6) dx. The problem involves using the integration by parts technique, assigning u = ln(9x).

Solution

The problem in the image asks to evaluate the integral

ln(9x)x6dx\int \frac{\ln(9x)}{x^6} \, dx

and provides a clue: it suggests using integration by parts, with u=ln(9x)u = \ln(9x).

The integration by parts formula is:

udv=uvvdu\int u \, dv = uv - \int v \, du

Step 1: Define uu and dvdv

Let:

  • u=ln(9x)u = \ln(9x), which implies du=1xdxdu = \frac{1}{x} \, dx,
  • dv=1x6dxdv = \frac{1}{x^6} \, dx, which implies v=15x5v = -\frac{1}{5x^5}.

Step 2: Apply integration by parts

Using the formula udv=uvvdu\int u \, dv = uv - \int v \, du, we substitute:

ln(9x)x6dx=ln(9x)(15x5)(15x5)1xdx\int \frac{\ln(9x)}{x^6} \, dx = \ln(9x) \cdot \left(-\frac{1}{5x^5}\right) - \int \left(-\frac{1}{5x^5}\right) \cdot \frac{1}{x} \, dx

This will simplify into the sum of two functions: F(x)F(x) and the integral of G(x)dxG(x) \, dx.

Step 3: Identify F(x)F(x) and G(x)G(x)

From the integration by parts result:

  • F(x)F(x) is the term ln(9x)(15x5)=ln(9x)5x5\ln(9x) \cdot \left(-\frac{1}{5x^5}\right) = -\frac{\ln(9x)}{5x^5},
  • G(x)G(x) is the function in the remaining integral, which is 15x6\frac{1}{5x^6}.

Thus:

  • F(x)=ln(9x)5x5F(x) = -\frac{\ln(9x)}{5x^5},
  • G(x)=15x6G(x) = -\frac{1}{5x^6}.

Would you like more details on the integration process or have any further questions?

Here are 5 related questions for further exploration:

  1. How is the integration by parts rule derived?
  2. What are some practical applications of integration by parts?
  3. How would this integral change if ln(9x)\ln(9x) were replaced with ln(x)\ln(x)?
  4. What happens if we reverse the roles of uu and dvdv in integration by parts?
  5. Can the integration by parts method be applied to definite integrals?

Tip: When performing integration by parts, always choose uu such that its derivative simplifies the integral.

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Math Problem Analysis

Mathematical Concepts

Calculus
Integration by Parts
Logarithmic Functions

Formulas

Integration by Parts Formula: ∫u dv = uv - ∫v du
Logarithmic differentiation: d(ln(x))/dx = 1/x

Theorems

Integration by Parts Theorem

Suitable Grade Level

University Level (Calculus)