Math Problem Statement

First use the substitution method to find the indefinite integral of \( \int 6x^5 (x^6)^5 \, dx \). Then find it without using substitution and check whether the answers are equivalent.

Solution

To solve this integral using substitution, let's analyze the given expression:

6x5(x6)5dx\int 6x^5 \left( x^6 \right)^5 \, dx

Step 1: Substitution

To simplify the integral, we can use substitution. Let's set: u=x6u = x^6 Then, taking the derivative of both sides with respect to xx: dudx=6x5dx=du6x5\frac{du}{dx} = 6x^5 \Rightarrow dx = \frac{du}{6x^5}

This substitution means that 6x5dx=du6x^5 \, dx = du. Rewriting the integral in terms of uu: 6x5(x6)5dx=u5du\int 6x^5 \left( x^6 \right)^5 \, dx = \int u^5 \, du

Step 2: Integrate with respect to uu

Now we integrate: u5du=u66+C\int u^5 \, du = \frac{u^6}{6} + C

Step 3: Substitute back u=x6u = x^6

Now, replace uu with x6x^6: u66+C=(x6)66+C=x366+C\frac{u^6}{6} + C = \frac{(x^6)^6}{6} + C = \frac{x^{36}}{6} + C

So, the result of the integration is: 6x5(x6)5dx=x366+C\int 6x^5 \left( x^6 \right)^5 \, dx = \frac{x^{36}}{6} + C

Verifying Without Substitution

Notice that (x6)5=x30\left( x^6 \right)^5 = x^{30}, so the integral can be rewritten as: 6x5x30dx=6x35dx\int 6x^5 \cdot x^{30} \, dx = \int 6x^{35} \, dx

Now integrate directly: 6x35dx=6x3636+C=x366+C\int 6x^{35} \, dx = 6 \cdot \frac{x^{36}}{36} + C = \frac{x^{36}}{6} + C

Both methods give the same result: x366+C\frac{x^{36}}{6} + C

Would you like more details on any of the steps?

Related Questions

  1. How do we determine the substitution variable for complex integrals?
  2. Why is the derivative of x6x^6 equal to 6x56x^5?
  3. What is the importance of confirming results using different methods?
  4. How does substitution simplify certain integrals?
  5. Can this substitution method be used for all power integrals?

Tip

When dealing with powers inside a function, consider substitution for simplification. This often reduces complex powers and expressions into simpler ones to integrate.

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Math Problem Analysis

Mathematical Concepts

Integration
Substitution Method
Exponents

Formulas

Substitution: Let u = f(x), then \( \int f'(x)g(f(x))dx = \int g(u) du \)
Power Rule for Integration: \( \int x^n dx = \frac{x^{n+1}}{n+1} + C \)

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12