Problem 49 - Precalculus with Limits

Question

Write the logarithmic equation in exponential form. \(\ln \frac{1}{2}=-0.693 \ldots\)

Step-by-Step Solution

Answer

The exponential form of the given logarithmic equation \( \ln \frac{1}{2}=-0.693 \ldots \) is \( e^{-0.693} = \frac{1}{2} \)

Step 1: Identify the parts of the logarithm

In our logarithm, the base is e (denoted by \( ln \) which stands for 'logarithm naturalis' or natural logarithm), the argument is \( \frac{1}{2} \) and the result is \( -0.693... \). This can be denoted by \( \log_e (\frac{1}{2}) = -0.693... \)

Step 2: Convert to exponential form

The conversion from logarithmic to exponential form is based on the definition of a logarithm: 'A logarithm base b of a number x is an exponent y such that the base b raised to the power of y is equal to the number x'. So, in our case, the base is e, the exponent is -0.693, and the number is \( \frac{1}{2} \). Meaning \( e^{-0.693} = \frac{1}{2} \). This is the required exponential form of the given logarithm.

Key Concepts

Exponential Form

The exponential form of a logarithmic equation involves expressing the equation such that a base number is raised to an exponent to produce a specific number. Essentially, it's the inverse operation of taking a logarithm. When we have a logarithmic equation, it states that a certain exponent for the base will yield the argument of the logarithm as its result.
For example, we start with a logarithmic equation such as \(ln \frac{1}{2} = -0.693\ldots\). The "ln" signifies that we are dealing with the natural logarithm, which has a base of \(e\). In converting this logarithmic equation to its exponential form, we follow these simple steps:

• Identify the base, which is \(e\) for natural logarithms.
• Note the exponent, which is the result of the logarithm, \(-0.693\ldots\).
• Recognize the argument of the logarithm, which in this case is \(\frac{1}{2}\).

So, when this equation is expressed in exponential form, it shows \(e^{-0.693} = \frac{1}{2}\). This transformation is based on the core logarithmic property that the base raised to the exponent results in the argument.

Natural Logarithm

Natural logarithms, often abbreviated as 'ln', are a special kind of logarithmic function where the base is the constant \(e\), approximately equal to 2.718. This constant is particularly important in mathematics and is the foundation of continuous growth and decay processes.
Natural logarithms have unique properties that make them quite useful:

• The base \(e\) connects deeply with calculus and natural growth processes, like populations or investments.
• They transform multiplicative processes into additive ones through their logarithmic properties.
• They are used to solve equations where the unknown is in the exponent.

Understanding natural logarithms is crucial when dealing with continuous exponential growth or decay. Moreover, the "ln" is what differentiates base \(e\) from other logarithmic bases, like base 10 or base 2. For instance, the equation \(\ln \frac{1}{2} = -0.693\ldots\) exemplifies the way natural logs quantify how many times you multiply \(e\) to get to \(\frac{1}{2}\).

Base e

Base \(e\) is a fundamental concept in mathematics, especially in fields involving calculus and complex analyses. The number \(e\) is an irrational number, approximately equal to 2.718, and it represents the limit of \((1 + \frac{1}{n})^n\) as \(n\) approaches infinity.
Here are some critical points about base \(e\):

• It serves as the base for natural logarithms, meaning all computations involving "ln" will use \(e\).
• The uniqueness of \(e\) is that it simplifies many formulas in mathematics, particularly in calculus, like the calculation of compounding interest.
• Base \(e\) functions are often seen in real-world phenomena such as radioactive decay and population growth.

When log equations are converted to exponential form, base \(e\) is a common factor, because it encapsulates properties of continuous growth. For instance, in the exponential equation \(e^{-0.693} = \frac{1}{2}\), we see \(e\) as the base helping us interpret logarithmic expressions in an exponential context.