Chapter 7: Problem 19
evaluate the integral, and check your answer by differentiating. $$\int\left[\frac{2}{x}+3 e^{x}\right] d x$$
Short Answer
Expert verified
The integral is \( 2\ln |x| + 3e^x + C \).
Step by step solution
01
Identify the Integral Components
The integral \( \int \left[\frac{2}{x}+3 e^{x}\right] dx \) consists of two separate functions: \( \frac{2}{x} \) and \( 3e^x \). We'll address each term individually.
02
Integrate the First Term
The first term is \( \frac{2}{x} \). The integral of \( \frac{1}{x} \) is \( \ln |x| \). Therefore, the integral of \( \frac{2}{x} \) is \( 2 \ln |x| \).
03
Integrate the Second Term
The second term is \( 3e^x \). The integral of \( e^x \) is \( e^x \). Therefore, the integral of \( 3e^x \) is \( 3e^x \).
04
Combine the Results
Combine the integrals from Step 2 and Step 3: \( \int \left[\frac{2}{x} + 3e^x \right] dx = 2\ln |x| + 3e^x + C \), where \( C \) is the constant of integration.
05
Differentiate to Verify
Differentiate the resultant expression: \( F(x) = 2\ln |x| + 3e^x + C \). The derivative of \( 2\ln |x| \) is \( \frac{2}{x} \) and the derivative of \( 3e^x \) is \( 3e^x \). Therefore, \( F'(x) = \frac{2}{x} + 3e^x \), which matches the original integrand.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Differentiation
Differentiation is a fundamental concept in calculus used to determine the rate at which a function changes at any given point. In simpler terms, it tells us how a function's values are changing instantaneously.
Think of it as finding the slope of a curve at a particular point. This not only provides insights into the behavior of a function but also allows us to find tangents and optimize performance in various applications.
Think of it as finding the slope of a curve at a particular point. This not only provides insights into the behavior of a function but also allows us to find tangents and optimize performance in various applications.
- Differentiation helps in understanding motion and rates of change, like velocity.
- It is crucial in determining maxima and minima for function optimization problems.
- It provides a way to check if an integral solution is correct by reversing the process of integration.
Natural Logarithm
The natural logarithm, denoted as \(\ln(x)\), is a logarithm to the base "e", where "e" is an irrational and transcendental number approximately equal to 2.71828. It is a fundamental mathematical constant, frequently popping up in calculus, particularly when dealing with rates of growth or decay.
- Natural logarithms transform multiplicative processes into additive ones, simplifying complex calculations.
- They are instrumental in solving equations involving exponential decay or growth models.
- The integral of \(\frac{1}{x}\) is a prime example of where the natural logarithm naturally appears in calculus: \(\int \frac{1}{x} \, dx = \ln |x| + C\).
Exponential Function
Exponential functions are equations where the variable appears in the exponent, such as \(e^x\). These functions are pivotal in modeling continuous growth processes, like population growth, radioactivity, or investment growth.
The base "e" provides a unique and natural growth pattern, frequently used in economic and scientific computations.
The base "e" provides a unique and natural growth pattern, frequently used in economic and scientific computations.
- The exponential function \(e^x\) remains unaffected by differentiation, meaning the derivative of \(e^x\) is always \(e^x\).
- Exponential growth models can be simplified with exponential functions, making them practical in real-world applications.
- Integrating \(3e^x\) yields \(3e^x\) once more, capturing the growth rate directly in its function.