Evaluate 2 √x (x²-1) 8 d dx

Calculus For The Life Sciences
2nd Edition
ISBN:9780321964038
Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Chapter7: Integration
Section7.2: Substitution
Problem 1E: Integration by substitution is related to what differentiation method? What type of integrand...
icon
Related questions
Question
## Evaluating the Integral

Assess the following integral:

\[
\int_{1}^{2} x (x^2 - 1)^8 \, dx
\]

### Explanation

In this problem, we aim to compute the definite integral of the function \( x (x^2 - 1)^8 \) from the lower limit of \(1\) to the upper limit of \(2\).

### Step-by-Step Solution

1. **Substitution Method**: Consider using substitution to simplify the integral. Let:
    \[
    u = x^2 - 1
    \]
    Then, differentiate both sides to find \(du\):
    \[
    \frac{du}{dx} = 2x \implies du = 2x \, dx \implies \frac{du}{2} = x \, dx
    \]

2. **Change of Variables**: Substitute \(u\) and \(du\) back into the integral. 
    - When \( x = 1 \):
      \[
      u = 1^2 - 1 = 0
      \]
    - When \( x = 2 \):
      \[
      u = 2^2 - 1 = 3
      \]

    Thus, the integral limits change from \(x = 1\) to \(x = 2\) into \(u = 0\) to \(u = 3\), and the integral becomes:
    \[
    \int_{0}^{3} (u)^8 \cdot \frac{du}{2}
    \]

3. **Simplify**: Simplify the integrand before integrating:
    \[
    \frac{1}{2} \int_{0}^{3} u^8 \, du
    \]
    
4. **Integrate**: Now integrate with respect to \(u\):
    \[
    \frac{1}{2} \left[ \frac{u^9}{9} \right]_{0}^{3}
    \]
    
5. **Evaluate the Definite Integral**:
    \[
    \frac{1}{2} \left( \frac{3^9}{9} - \frac{0^9}{9} \right) = \frac{1}{2} \cdot \frac{3^9}{9} = \
Transcribed Image Text:## Evaluating the Integral Assess the following integral: \[ \int_{1}^{2} x (x^2 - 1)^8 \, dx \] ### Explanation In this problem, we aim to compute the definite integral of the function \( x (x^2 - 1)^8 \) from the lower limit of \(1\) to the upper limit of \(2\). ### Step-by-Step Solution 1. **Substitution Method**: Consider using substitution to simplify the integral. Let: \[ u = x^2 - 1 \] Then, differentiate both sides to find \(du\): \[ \frac{du}{dx} = 2x \implies du = 2x \, dx \implies \frac{du}{2} = x \, dx \] 2. **Change of Variables**: Substitute \(u\) and \(du\) back into the integral. - When \( x = 1 \): \[ u = 1^2 - 1 = 0 \] - When \( x = 2 \): \[ u = 2^2 - 1 = 3 \] Thus, the integral limits change from \(x = 1\) to \(x = 2\) into \(u = 0\) to \(u = 3\), and the integral becomes: \[ \int_{0}^{3} (u)^8 \cdot \frac{du}{2} \] 3. **Simplify**: Simplify the integrand before integrating: \[ \frac{1}{2} \int_{0}^{3} u^8 \, du \] 4. **Integrate**: Now integrate with respect to \(u\): \[ \frac{1}{2} \left[ \frac{u^9}{9} \right]_{0}^{3} \] 5. **Evaluate the Definite Integral**: \[ \frac{1}{2} \left( \frac{3^9}{9} - \frac{0^9}{9} \right) = \frac{1}{2} \cdot \frac{3^9}{9} = \
Expert Solution
steps

Step by step

Solved in 4 steps with 4 images

Blurred answer
Recommended textbooks for you
Calculus For The Life Sciences
Calculus For The Life Sciences
Calculus
ISBN:
9780321964038
Author:
GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:
Pearson Addison Wesley,