Chapter 7: Problem 13
Use radical notation to write each expression. Simplify if possible. $$ (-27)^{1 / 3} $$
Short Answer
Expert verified
The expression simplifies to -3.
Step by step solution
01
Understand Radical Notation
The expression is given in exponential form as \[(-27)^{1/3}\] To write it in radical notation, remember that \[a^{1/n} = \sqrt[n]{a}\]This means we need to express the cube root of -27.
02
Write in Radical Form
Using the rule from Step 1, \[(-27)^{1/3}\] can be rewritten using radical notation as \[\sqrt[3]{-27}\] This notation means 'the cube root of -27'.
03
Simplify the Radical Expression
We need to find the cube root of -27. The cube root of a negative number is negative, and since \[(-3) \times (-3) \times (-3) = -27\] we have: \[\sqrt[3]{-27} = -3\] So the expression simplifies to -3.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Cube Root
The cube root of a number is an operation that determines what number, when multiplied by itself twice (in total, three times), will equal the given number. When dealing with a cube root, a number inside the radical symbol, we are essentially asking the question: "What number times itself three times gives me this result?"
It can be denoted as \(\sqrt[3]{a}\) where 3 is the index, indicating the cube root. In our example, \(\sqrt[3]{-27}\) represents "what number cubed equals -27?".
Recalling cube roots is crucial, especially when the number is negative. A useful tip is recognizing patterns in small integer powers:
It can be denoted as \(\sqrt[3]{a}\) where 3 is the index, indicating the cube root. In our example, \(\sqrt[3]{-27}\) represents "what number cubed equals -27?".
Recalling cube roots is crucial, especially when the number is negative. A useful tip is recognizing patterns in small integer powers:
- The cube root of -27 is -3, since \((-3) \times (-3) \times (-3) = -27\).
- The cube root and cube function are inverse operations.
Exponential Form
Exponential form is a way to express numbers by raising them to a fraction or whole number power. The general idea is that a number, referred to as the base, is increased by multiplying itself a certain number of times. This is represented as \(a^n\), where \(a\) is the base and \(n\) is the exponent.
In the given problem, \((-27)^{1/3}\), \(-27\) is the base, and \(1/3\) is the exponent. This indicates we are supposed to find the cube root of \(-27\).
Some key points about exponential form include:
In the given problem, \((-27)^{1/3}\), \(-27\) is the base, and \(1/3\) is the exponent. This indicates we are supposed to find the cube root of \(-27\).
Some key points about exponential form include:
- An exponent of \(1/3\) corresponds to taking the cube root.
- Exponential notation provides a compact way to express roots and repeated multiplication.
- It helps in simplifying expressions by converting between radical and exponential forms.
Simplifying Expressions
Simplifying expressions means breaking down a complex expression into the simplest form. For the task at hand, we rewrite the expression to make calculations manageable while retaining the expression’s original value.
For \((-27)^{1/3}\), which equals \(\sqrt[3]{-27}\), simplifying this requires evaluating the cube root of \(-27\).
For \((-27)^{1/3}\), which equals \(\sqrt[3]{-27}\), simplifying this requires evaluating the cube root of \(-27\).
- Knowing that \(-3 \times -3 \times -3 = -27\), we determine \(\sqrt[3]{-27} = -3\).
- Simplifying often involves recognizing known powers and roots.
- Solving cube roots can include factoring numbers if straightforward calculations become complex.
Negative Numbers
Negative numbers are numbers less than zero and are usually denoted with a minus sign. Working with negative numbers, especially when dealing with roots and powers, follows specific rules.
When computing the cube root of a negative number, such as \(-27\), it's important to recognize that the results remain in the negative form due to the properties of multiplication:
When computing the cube root of a negative number, such as \(-27\), it's important to recognize that the results remain in the negative form due to the properties of multiplication:
- The cube of a negative number is always negative, explaining \((-3)^3 = -27\).
- Cube roots of negative numbers will yield negative results due to the symmetry of the operation.
- Handling negative bases and fractional exponents like \((-27)^{1/3}\) is crucial for accurate results.