Problem 30 - Elementary Algebra

Question

Write the expressions for the following problems using only positive exponents. $$ c^{-6} $$

Step-by-Step Solution

Answer

Question: Rewrite the given expression with a negative exponent using only positive exponents: $$c^{-6}$$ Answer: $$\frac{1}{c^6}$$

Step 1: Recall the rules for negative exponents.

Remember that a negative exponent means division by the base raised to the positive value of the exponent. In other words, if we have an expression like a^{-n}, it can be rewritten as \frac{1}{a^n}.

Step 2: Apply the rules to the given expression.

In our case, the expression is c^{-6}. Based on the rule mentioned in Step 1, we can rewrite it as: $$ \frac{1}{c^6} $$ So, the given expression with only positive exponent is:$$ \frac{1}{c^6} $$

Key Concepts

Exponential Expressions

When we encounter an exponential expression, we are dealing with a compact way to represent repeated multiplication of the same base. For example, when we write \(2^5\), it stands for \(2\times 2\times 2\times 2\times 2\). These expressions are incredibly useful in a wide variety of mathematical fields, from simple algebra to complex calculus.

However, it's essential to understand the different types of exponents, particularly when they are negative. A negative exponent, such as \(c^{-6}\), indicates division, as opposed to the multiplication suggested by a positive exponent. This concept is a vital tool in simplifying expressions and solving equations. A key thing to remember is that any base, excluding zero, raised to a negative exponent equals the reciprocal of that base raised to the corresponding positive exponent. This reciprocal nature is neatly described by the formula \(a^{-n} = \frac{1}{a^n}\), where \(a\) represents the base, and \(n\) is a positive integer.

Understanding exponential expressions with negative exponents lays the groundwork for working with more advanced concepts, such as exponential growth and decay in functions or even in financial models that compute compound interest.

Positive Exponents

Moving to the concept of positive exponents, these are what most people initially learn in math. They represent the basic idea of multiplying a number by itself a certain number of times. As we've seen, \(c^6\) indicates multiplying \(c\) by itself six times.

To convert a negative exponent to a positive one, as demonstrated in the exercise with \(c^{-6}\), you would rewrite the expression as \(\frac{1}{c^6}\), making the exponent positive. It's a common mistake to assume that a negative exponent makes the number itself negative, which is not the case; the negativity only affects the placement of the number in a fraction format.

Why Positive Exponents Matter

In science and engineering, positive exponents are used to express large quantities, such as distances in space or the speed of light. In finance, they are used to calculate compound interest over multiple periods. Essentially, mastering positive exponents is necessary for cumulative multiplication across various practical and theoretical applications.

Algebraic Expressions

Lastly, algebraic expressions are combinations of letters and numbers using arithmetic operations. They are the building blocks of algebra and form the language through which we communicate abstract mathematical ideas. When exponents are part of these expressions, they indicate how many times a variable is multiplied by itself.

The expression \(c^{-6}\) is an algebraic expression with a negative exponent. However, it's a common goal in algebra to rewrite expressions to reflect certain standards or solve equations. Therefore, expressions with negative exponents are often restated as rational expressions with positive exponents, revealing their underlying value without the immediate impression of division.

Simplifying Expressions

The process of simplifying like the one seen in our original exercise, where \(c^{-6}\) is rewritten as \(\frac{1}{c^6}\), serves multiple purposes. It can make the evaluation of the expression easier, or it could be a necessary step in solving for a variable. Algebraic expressions become far more manageable when the fundamental rules of exponents are applied, which is why understanding negative and positive exponents is crucial for any student of algebra.