Chapter 4: Problem 19
Solve the following equations for \(x.\) $$e^{2 x}=5$$
Short Answer
Expert verified
x = \frac{\ln(5)}{2}.
Step by step solution
01
- Take the Natural Logarithm of Both Sides
In order to solve the equation, start by taking the natural logarithm (ln) of both sides of the given equation o.e^{2x} = 5.This step helps us bring down the exponent involving x. Therefore, applying the natural logarithm to both sides gives \[\ln(e^{2x}) = \ln(5).\]
02
- Simplify the Left Side
Using the logarithm power rule, \[\ln(e^a) = a,\]we can simplify the left side of the equation. Therefore, \[\ln(e^{2x}) = 2x.\]So now, the equation becomes \[2x = \ln(5).\]
03
- Solve for x
To isolate x, divide both sides of the equation by 2: \[x = \frac{\ln(5)}{2}.\]This gives the solution for x.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Exponential Functions
Exponential functions are a powerful way to represent a wide range of phenomena, from population growth to radioactive decay. The general form of an exponential function is \[ f(x) = a \times b^x \] where \[a\] is the initial value, \[b\] is the base, and \[x\] is the exponent. In the original problem, the equation is \[ e^{2x} = 5 \], which is an exponential equation with base \[e\], the natural logarithm base approximately equal to 2.718. Exponential functions have unique properties:
- Their growth rate becomes faster as the value of \[x\] increases.
- They can be used to model exponential growth or decay situations effectively.
- The base \[e\] is especially important in natural processes, making it crucial in calculus and differential equations.
Logarithm Properties
Logarithms are the inverse operations to exponentiation. If you have \[ b^x = y \], the logarithm base \[b\] of \[y\] is \[ \text{log}_b(y) = x \]. In the natural logarithm case, the base is \[e\] and notated as \[ \text{ln}(y) \]. Here are some key logarithm properties that help in manipulating and solving equations:
\[ \text{ln}(e^{2x}) = 2x \]. This property allows us to bring down the exponent \[2x\], making the equation solvable using basic algebraic techniques.
- Product Property: \[ \text{log}_b(x \times y) = \text{log}_b(x) + \text{log}_b(y) \]
- Quotient Property: \[ \text{log}_b\frac{x}{y} = \text{log}_b(x) - \text{log}_b(y) \]
- Power Property: \[ \text{log}_b(x^a) = a \times \text{log}_b(x) \]
- Change of Base Formula: \[ \text{log}_b(y) = \frac{\text{log}_k(y)}{\text{log}_k(b)} \]
\[ \text{ln}(e^{2x}) = 2x \]. This property allows us to bring down the exponent \[2x\], making the equation solvable using basic algebraic techniques.
Solving Equations
Solving equations, especially exponential ones, often involves isolating the variable to one side. Here's a detailed guide:
- Taking the Logarithm: When dealing with exponential equations, the first step is generally to take the natural logarithm \[ \text{ln} \] (or any logarithm relevant to the equation) on both sides. For \[ e^{2x} = 5 \], we get \[ \text{ln}(e^{2x}) = \text{ln}(5) \].
- Using Logarithm Properties: Utilize properties like the power rule to bring the exponent in front. So, \[ \text{ln}(e^{2x}) = 2x \] brings down the \[2x\].
- Isolating the Variable: Reorganize the equation to solve for \[x\]. In the problem, you do this by dividing both sides by 2, resulting in \[ x = \frac{\text{ln}(5)}{2} \].
- Finalizing the Solution: Simplify the equation to find the value of \[ x \] clearly.