Problem 44 - College Algebra and Calculus: An Applied Approach

Question

Simplify the expression.\(2^{m} \cdot 2^{3 m}\)

Step-by-Step Solution

Answer

The simplified form of the expression \(2^{m} \cdot 2^{3 m}\) is \(2^{4 m}\).

Step 1: Identify the base

By looking at the expression \(2^{m} \cdot 2^{3 m}\) we can see that the base for both terms is 2.

Step 2: Apply the rule of exponents

Applying the rule of exponents, \(a^{m} \cdot a^{n} = a^{m+n}\), we can add up the exponents (m and 3m in this case) since they have the same base 2. This equates to \(2^{m + 3 m}\)

Step 3: Simplify the exponent

Add the terms m and 3m to get 4m. The expression therefore simplifies to \(2^{4 m}\)

Key Concepts

Rules of Exponents

Understanding how to manipulate powers is essential in algebra, especially when dealing with exponential expressions. One fundamental rule is the Product of Powers rule which states that when multiplying two exponents with the same base, you can simply add the exponents together. This rule is written as \( a^m \cdot a^n = a^{m+n} \). In our exercise, we identified that \(2^{m} \cdot 2^{3m}\) has a common base of 2. Thus, we apply the rule by adding up the exponents: \( m + 3m = 4m \) to simplify the expression to \(2^{4m}\).
Other critical rules include the Power of a Power rule (\( (a^m)^n = a^{mn} \) ) and the Quotient of Powers rule (\( \frac{a^m}{a^n} = a^{m-n} \)). Mastery of these rules is key to tackling more complex algebraic problems involving exponential expressions.

Exponential Functions

An exponential function is a mathematical expression where a constant base is raised to a variable exponent. This form is written as \( f(x) = a^x \), where \( a \) is a positive real number, and \( x \) is the exponent. In the context of our exercise, the expression \(2^{m} \cdot 2^{3m}\) simplifies to an exponential function \(2^{4m} \), where 2 is the constant base and \(4m \) the variable exponent. Exponential functions exhibit rapid growth or decay and are used to model an array of real-world phenomena, such as population growth, radioactive decay, and interest calculations.

Algebraic Manipulation

Algebraic manipulation refers to the process of rearranging and simplifying mathematical expressions and equations. During this process, you might employ a variety of techniques such as distributing, factoring, combining like terms, and applying exponent rules. In our textbook example, the simplification \(2^{m} \cdot 2^{3m} = 2^{4m}\) is a straightforward instance of algebraic manipulation, emphasizing the need to recognize similar terms—in this case, exponents with like bases—and combine them appropriately.

Exponent Properties

Exponents are not just numbers on top of other numbers; they're a shorthand for repeated multiplication and have specific properties that make calculations much easier. Apart from the Product of Powers rule already discussed, exponent properties include the Zero Exponent rule (\( a^0 = 1 \) for any non-zero \( a \)), the Negative Exponent rule (\( a^{-n} = \frac{1}{a^n} \)), and the Fractional Exponent rule where \( a^{\frac{1}{n}} \) is the nth root of \( a \). These properties are essential for simplifying complex expressions and solving equations containing exponents. A firm grasp of these properties is an invaluable asset in algebra.