Chapter 5: Problem 77
Perform the operations. $$ (2 m+n)^{3} $$
Short Answer
Expert verified
The expanded form of \\( (2m + n)^3 \\) is \\(8m^3 + 12m^2n + 6mn^2 + n^3\\).
Step by step solution
01
Identify the Expansion Formula
We will use the binomial theorem to expand \(a + b\)^n. The formula is \((a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^{k}\). In this problem, \(a = 2m\), \(b = n\), and \(n = 3\).
02
Compute the Binomial Coefficients
For \(n = 3\), the binomial coefficients \(\binom{3}{k}\) are found for \(k = 0, 1, 2, 3\). These are \(1, 3, 3, 1\).
03
Apply the Binomial Expansion
Express \( (2m + n)^3 \) using the coefficients and terms. It becomes: \( 1 \cdot (2m)^3 \cdot n^0 + 3 \cdot (2m)^2 \cdot n^1 + 3 \cdot (2m)^1 \cdot n^2 + 1 \cdot (2m)^0 \cdot n^3 \).
04
Simplify Each Term
Calculate each term: - \((2m)^3 \) = \(8m^3\).- \(3 \cdot (2m)^2 \cdot n \) = \(3 \cdot 4m^2 \cdot n = 12m^2n\).- \(3 \cdot (2m) \cdot n^2 \) = \(6mn^2\).- \((n)^3\) = n^3\.
05
Write the Final Expression
Combine all terms to get the final expanded form: \(8m^3 + 12m^2n + 6mn^2 + n^3\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Binomial Expansion
The binomial expansion is a technique used in algebra to expand expressions that are raised to a power. This method is particularly useful when you have something like \((a + b)^n\), where a and b are any terms, and n is a positive integer.
The formula for binomial expansion is given by:
In our example, we're expanding \((2m + n)^3\). Use the formula and replace a with \(2m\), b with \(n\), and n with \(3\). In this way, the expansion becomes a sum of multiple terms, each of which needs to be evaluated individually.
The formula for binomial expansion is given by:
- \((a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^{k}\)
In our example, we're expanding \((2m + n)^3\). Use the formula and replace a with \(2m\), b with \(n\), and n with \(3\). In this way, the expansion becomes a sum of multiple terms, each of which needs to be evaluated individually.
Polynomial Expression
A polynomial expression is a mathematical expression composed of variables, coefficients, and non-negative integer exponents. For example, \(8m^3 + 12m^2 n + 6mn^2 + n^3\) is a polynomial.
When you break it down:
In this exercise, the original expression \((2m + n)^3\) was transformed into a polynomial expression through binomial expansion. The terms add up to form a full polynomial product that represents the expanded form of the original expression. Polynomials like this one appear often in algebra, as they are a fundamental part of mathematics.
When you break it down:
- Each term in the polynomial can have a coefficient (like 8, 12, or 6 in our final expression).
- The variables (like m and n) are raised to various powers, referred to as exponents.
In this exercise, the original expression \((2m + n)^3\) was transformed into a polynomial expression through binomial expansion. The terms add up to form a full polynomial product that represents the expanded form of the original expression. Polynomials like this one appear often in algebra, as they are a fundamental part of mathematics.
Exponents
Exponents are a mathematical notation indicating the number of times a base is multiplied by itself. For instance, in the expression \((2m)^3\), the exponent 3 means that \(2m\) is being multiplied by itself two more times, totaling three multiplications: \(2m \times 2m \times 2m\).
Understanding exponents helps with:
In this problem, the expression \((2m + n)^3\), the terms in the expansion will have exponents that add up to the original power, which is 3 in this case. As we've seen, working out each term means computing exponents like \((2m)^2\), \(n^2\), and even \(n^3\), reflecting how the power is distributed.
Understanding exponents helps with:
- Simplifying large numbers.
- Keeping track of how many times you multiply a number by itself.
In this problem, the expression \((2m + n)^3\), the terms in the expansion will have exponents that add up to the original power, which is 3 in this case. As we've seen, working out each term means computing exponents like \((2m)^2\), \(n^2\), and even \(n^3\), reflecting how the power is distributed.