Problem 68 - Introductory and Intermediate Algebra for College Students 4th

Question

Simplify each expression. $$\ln e^{13 x}$$

Step-by-Step Solution

Answer

The simplified form of \(\ln(e^{13x})\) is \(13x\).

Step 1: Identify the Expression

We need to evaluate or simplify: \(\ln e^{13 x}\).

Step 2: Apply Order of Operations

Following the order of operations (PEMDAS/BODMAS), we simplify the expression step by step, handling parentheses, exponents, multiplication/division, then addition/subtraction.

Step 3: Compute the Result

Carrying out the operations systematically, we arrive at the result.

Step 4: State the Result

The simplified form of \(\ln(e^{13x})\) is \(13x\).

Key Concepts

Logarithmic Identity

Logarithmic identities are incredibly helpful tools that simplify complex logarithmic expressions. These are based on the inherent properties of logarithms. For natural logarithms (ln), one key identity is that the natural logarithm of e raised to a power, say any number \(k\), simplifies to just \(k\). This is expressed as:

• \(\ln(e^k) = k\)

This identity arises because the base of the natural logarithm, e, and the natural exponential function (e to any power) are inverse operations.

To clarify, when we have \(\ln(e^{13x})\), we apply this identity directly. Since the base e and the natural log \(\ln\) are inverses, the expression simplifies instantly to \(13x\). Remembering this key identity can make working with natural logs much easier and saves time in calculations.

Exponential Functions

Exponential functions play a crucial role in mathematics. These functions are of the form \(e^x\), where \(e\) is a constant approximately equal to 2.71828.

• An exponential function involves an exponent on the base \(e\).
• It increases (or decreases) rapidly.

Exponential functions are used in diverse fields, including biology, finance, and physics for modeling growth and decay.

One distinguishing feature is the rate of change in an exponential function. This rate increases as the value of \(x\) increases if the exponent is positive, leading to exponential growth. Conversely, it exhibits exponential decay if the exponent is negative. Recognizing these functions and their properties helps you understand how they work especially when they interact with logarithmic functions.

Simplifying Expressions

Simplifying expressions is the process of making them more manageable or easier to work with, whilst keeping their value unchanged. This usually involves applying mathematical rules and properties.

• When simplifying logarithmic expressions, like \(\ln(e^{13x})\), recognizing identities and properties is key.
• Using properties like \(\ln(e^k)=k\) helps in reducing complexity.

In this context, simplifying becomes straightforward when applying known identities. You simply translate the original expression into an easier form, such as reducing \(\ln(e^{13x})\) to \(13x\).

Simplifying expressions makes them easier to interpret or use in further mathematical operations. It is a vital skill that underpins many algebraic processes and simplifies computational work.