Math Problem Statement

Evaluate the indefinite integral: ∫x^2 (x^3 + 5)^(3/2) dx

Solution

To solve the given indefinite integral:

x2(x3+5)3/2dx\int x^2 \left(x^3 + 5\right)^{3/2} dx

Solution:

  1. Substitution: Let u=x3+5u = x^3 + 5. Then, du=3x2dxdu = 3x^2 dx, or x2dx=13dux^2 dx = \frac{1}{3} du.

  2. Rewriting the integral: Substitute uu and x2dxx^2 dx: x2(x3+5)3/2dx=(u3/2)13du\int x^2 \left(x^3 + 5\right)^{3/2} dx = \int \left(u^{3/2}\right) \frac{1}{3} du

    Simplify: 13u3/2du\frac{1}{3} \int u^{3/2} du

  3. Integrate: Use the power rule for integration: undu=un+1n+1,for n1\int u^n du = \frac{u^{n+1}}{n+1}, \quad \text{for } n \neq -1

    Here, n=32n = \frac{3}{2}, so: u3/2du=u5/25/2=25u5/2\int u^{3/2} du = \frac{u^{5/2}}{5/2} = \frac{2}{5} u^{5/2}

    Multiply by 13\frac{1}{3}: 1325u5/2=215u5/2\frac{1}{3} \cdot \frac{2}{5} u^{5/2} = \frac{2}{15} u^{5/2}

  4. Substitute back: Recall u=x3+5u = x^3 + 5: 215(x3+5)5/2+C\frac{2}{15} (x^3 + 5)^{5/2} + C

Final Answer:

x2(x3+5)3/2dx=215(x3+5)5/2+C\int x^2 \left(x^3 + 5\right)^{3/2} dx = \frac{2}{15} (x^3 + 5)^{5/2} + C


Would you like further clarification or a step-by-step breakdown of any part?

Related Questions:

  1. How can substitution simplify other types of integrals?
  2. What are the conditions for applying the power rule in integration?
  3. How do we identify the best substitution for a given integral?
  4. Can you provide examples where substitution doesn't work as effectively?
  5. How do definite integrals differ from indefinite ones when solving using substitution?

Tip:

When using substitution, always ensure that the derivative of your substitution matches part of the integrand for smoother integration!

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Math Problem Analysis

Mathematical Concepts

Calculus
Integration
Substitution Method

Formulas

Substitution: Let u = g(x) and du = g'(x)dx
Power Rule for Integration: ∫u^n du = (u^(n+1))/(n+1) + C for n ≠ -1

Theorems

Power Rule of Integration

Suitable Grade Level

Grades 11-12, College Calculus