Problem 87 - Algebra and Trigonometry Real Mathematics, Real People

Question

Use the properties of natural logarithms to rewrite the expression. $$\ln e^{\ln e}$$

Step-by-Step Solution

Answer

The simplified expression of \(\ln e^{\ln e}\) is 1.

Step 1: Apply the power rule

The power rule of logarithms \(ln(a^b) = b*ln(a)\) can be applied to \(\ln e^{\ln e}\) yielding \(\ln e * \ln e\).

Step 2: Apply the base rule

Now, use the rule \(ln_e(e) = 1\), to further simplify the expression. Hence, \(\ln e * \ln e\) becomes \(1 * 1\).

Step 3: Calculate the product

Calculate the product of \(1 * 1\), which gives us the result \(1\).

Key Concepts

Power Rule of Logarithms

Understanding the power rule of logarithms is crucial for simplifying complex logarithmic expressions. Essentially, the power rule is an algebraic property that states that the logarithm of a power is the exponent times the logarithm of the base, which is mathematically represented as
\( \text{if } b > 0 \text{ and } b eq 1 \text{, then } \text{log}_b(a^c) = c \times \text{log}_b(a) \).

This property is exceptionally useful when tackling expressions with exponents inside a logarithm. For example, with the expression \( \text{log}_b(x^r) \), instead of computing the value of \( x^r \) first and then the logarithm, you can simply multiply \( r \) by \( \text{log}_b(x) \) to simplify the expression.

When applying this rule, remember that the base, in logarithmic terms, is the number that is raised to the power of the logarithm. To apply the power rule effectively, one should be comfortable with exponentiation and basic logarithmic identities.

Base e Logarithm

The base \( e \) logarithm, commonly known as the natural logarithm, is a logarithm to the base of the mathematical constant \( e \), where \( e \) is approximately equal to 2.71828. This base is particularly important in mathematics due to its natural properties in calculus and its appearance in various scientific and financial models.

The natural logarithm of a number \( x \) is written as \( \text{ln}(x) \), and it essentially answers the question: 'To what power do we raise \( e \) to get \( x \)?'. It's inherent in the equation \( e^y = x \), where \( y \) is calculated using \( y = \text{ln}(x) \).

In practical terms, when we refer to the 'natural logarithm' of \( e \), noted as \( \text{ln}(e) \), it is always equal to \( 1 \) because \( e \) is the base of natural logarithms. This identity is a key tool to simplify expressions involving \( e \) and its powers.

Natural Logarithm Simplification

Simplifying expressions using natural logarithms involves applying a series of properties and rules that govern logarithms. Natural logarithm simplification often leads to much more manageable expressions in which complex logarithmic terms are reduced to simpler, easier-to-calculate numbers.

Some simplification strategies include:

• Converting complex exponents to multiplication, using the power rule.
• Recognizing that the natural logarithm of \( e \), \( \text{ln}(e) \), is 1, due to the definition of base \( e \).
• Combining logarithms using properties such as the product rule (\( \text{ln}(ab) = \text{ln}(a) + \text{ln}(b) \)) and the quotient rule (\( \text{ln}(\frac{a}{b}) = \text{ln}(a) - \text{ln}(b) \)).

Through these techniques, simplification becomes a matter of recognizing patterns that align with logarithmic properties and applying the appropriate transformations to the expression. This skill enhances understanding and proficiency in dealing with logarithmic functions and your overall mathematical toolkit.