Question

Write the logarithm in terms of common logarithms.\(\log _{3} n\)

Short answer

The given logarithm in terms of common logarithms is expressed as: \(\log _{3} n = \frac{\log _{10} n}{\log _{10} 3}\).

Step-by-step solution

Application of Change of Base Formula

Now, let's apply the change of base formula on given logarithmic expression \(\log _{3} n\). Using change of base formula which is \(\log _{b} a = \frac{\log _{d} a}{\log _{d} b}\), where \(d\) is the new base (which is 10 for common logarithms), the given expression can be written as : \(\log _{3} n = \frac{\log _{10} n}{\log _{10} 3}\).

Key concepts

Logarithms

A logarithm is essentially the inverse of an exponentiation. It is a way to determine the power to which a given number, called the base, must be raised to produce another number. For example, if we have the equation \(b^x = a\), then the logarithm \(\log_b a\) equals \(x\). This relationship is crucial in many areas of mathematics and science, as it helps simplify complex multiplication and division processes into manageable additions and subtractions.

Logarithms come in various bases, with common examples being base 10 logarithms (common logarithms) and base \(e\) logarithms (natural logarithms). Understanding the properties of logarithms, such as the product, quotient, and power rules, can greatly assist in computations and solving exponential equations.

• The product rule states \(\log_b(MN) = \log_b M + \log_b N\).
• The quotient rule states \(\log_b\left(\frac{M}{N}\right) = \log_b M - \log_b N\).
• The power rule states \(\log_b(M^k) = k \cdot \log_b M\).

These rules are instrumental in expanding or condensing logarithmic expressions, making them fundamental tools in algebra.

Common Logarithms

Common logarithms use base 10, which makes them particularly handy in everyday applications and when dealing with decimal numbers. In mathematical notation, they are usually written simply as \(\log\) without the base, implying a base of 10. For example, \(\log_{10} 100 = 2\) because \(10^2 = 100\).

Common logarithms are widely used in sciences like chemistry and physics, where measurements often span multiple magnitudes. Tools like scientific calculators usually have a dedicated button just for common logarithms due to their prevalence. In solving logarithmic equations, using common logarithms simplifies calculations when the base is conveniently 10.

• When the base is omitted in a logarithmic expression, assume it is 10.
• Common logarithms convert multiplication of large numbers into addition, simplifying complex calculations.

They are especially useful for working with exponential growth or decay, such as population growth or radioactive decay rates.

Base 10

Base 10, often referred to as the decimal system, forms the foundation of common logarithms. The base 10 system is intuitive as humans naturally use it for counting and arithmetic due to the handy ten fingers we have. In logarithms, base 10 plays a similar crucial role. It simplifies the conversion of values into more comprehensible orders of magnitude, ideal for instances where growth or reduction is measured exponentially.

Understanding base 10 helps make sense of scientific notation, which expresses very large or small numbers in terms of powers of 10. For example, \(2.3 \times 10^5\) denotes the number 230,000. This is where common logarithms bridge the gap, as they allow for easy conversion between exponential values and their logarithmic forms.

• Base 10 helps in interpreting and expressing figures in a simplified manner, particularly in science and engineering.
• Knowledge of base 10 is essential for understanding metrics and standards like the pH scale or Richter scale which use logarithmic functions.

Mastering base 10 concepts strengthens your overall mathematical foundational skills and enhances your problem-solving capabilities in multiple real-world scenarios.