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Evaluate the integral by rewriting the integrand appropriately, if required, and applying the power rule (Formula 2 in Table \(5.2 .1\). (a) \(\int x^{8} d x\) (b) \(\int x^{5 / 7} d x\) (c) \(\int x^{3} \sqrt{x} d x\)

Short Answer

Expert verified
(a) \( \frac{x^9}{9} + C \), (b) \( \frac{7}{12} x^{12/7} + C \), (c) \( \frac{2}{9} x^{9/2} + C \).

Step by step solution

01

Understanding the Power Rule

The power rule for integration states: \[ \int x^n \, dx = \frac{x^{n+1}}{n+1} + C \]where \( n eq -1 \) and \( C \) is the constant of integration. We will use this rule to evaluate each integral.
02

Evaluating Integral (a)

For the integral \( \int x^8 \, dx \), we directly apply the power rule:\[ \int x^8 \, dx = \frac{x^{8+1}}{8+1} + C = \frac{x^9}{9} + C \].Thus, the evaluation of the integral results in \( \frac{x^9}{9} + C \).
03

Evaluating Integral (b)

For the integral \( \int x^{5/7} \, dx \), we again apply the power rule:\[ \int x^{5/7} \, dx = \frac{x^{5/7+1}}{5/7+1} + C = \frac{x^{12/7}}{12/7} + C. \]To simplify further, multiply by the reciprocal of \( \frac{12}{7} \):\[ \int x^{5/7} \, dx = \frac{7}{12} x^{12/7} + C. \]
04

Simplifying Integral (c)

Rewrite the integrand \( x^3 \sqrt{x} \) as a power of \( x \). Note that \( \sqrt{x} = x^{1/2} \). Therefore,\[ x^3 \sqrt{x} = x^3 \cdot x^{1/2} = x^{3 + 1/2} = x^{7/2}. \]Now, the integral becomes \( \int x^{7/2} \, dx \).
05

Evaluating Integral (c)

Apply the power rule to \( \int x^{7/2} \, dx \):\[ \int x^{7/2} \, dx = \frac{x^{7/2+1}}{7/2+1} + C = \frac{x^{9/2}}{9/2} + C. \]To simplify, multiply by the reciprocal of \( \frac{9}{2} \):\[ \int x^{7/2} \, dx = \frac{2}{9} x^{9/2} + C. \]

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Definite Integrals
In calculus, definite integrals are a way of calculating the total accumulation of a function over an interval. They provide the net area between the function and the x-axis over a specified range. When dealing with definite integrals, it's crucial to apply limits to the integral expression. This involves evaluating the indefinite integral at both boundaries and subtracting the result of the lower boundary from the result of the upper boundary.For example, when computing \[\int_{a}^{b} x^n \, dx,\] where \(a\) and \(b\) are the limits, the first step is to find the anti-derivative using the power rule. Then, substitute both limits into the solution and find the difference.Understanding definite integrals requires comfort with algebraic manipulation as well as the integration process itself. This concept establishes the foundation for other more complex calculus topics.
Integration Techniques
Integration techniques are methods used to find the integral of a function. One of the most common methods is the Power Rule. This rule simplifies the integration of polynomial expressions. It is especially useful when dealing with terms in the form of \(x^n\).To apply the Power Rule, simply increase the exponent by one and divide by the new exponent. Don’t forget to add the constant of integration, \(C\), for indefinite integrals. Applying this rule helps transform a complex integral expression into a more manageable form.Other integration techniques may include substitution and partial fraction decomposition, each essential for tackling more intricate integrals not readily simplified by the Power Rule. Integrating complex polynomial expressions often pairs well with algebraic manipulation to simplify the integrand first.
Algebraic Manipulation
Algebraic manipulation is key in calculus, especially when preparing an integrand for integration. It involves rewriting expressions to reveal hidden patterns or more familiar forms. This process makes it easier to apply integration techniques effectively.For instance, consider re-expressing terms like \(x^3\sqrt{x}\). Taking advantage of algebraic rules—such as the property that \(\sqrt{x} = x^{1/2}\)—we can rewrite it as \(x^{3 + 1/2} = x^{7/2}\). This transformation prepares the integrand for the Power Rule of integration. By simplifying the integrand algebraically, complex problems often yield straightforward solutions when approached systematically. It's crucial to ensure accuracy in these manipulations to apply further integration techniques successfully.

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