Chapter 10: Problem 51
Rationalize each numerator. Assume that all variables represent positive real numbers. \(\frac{\sqrt[3]{5 y^{2}}}{\sqrt[3]{4 x}}\)
Short Answer
Expert verified
The rationalized expression is \(\frac{5y^2}{\sqrt[3]{100xy^4}}\).
Step by step solution
01
Identify the Need to Rationalize
To rationalize the numerator of the expression \(\frac{\sqrt[3]{5 y^{2}}}{\sqrt[3]{4 x}}\), we need to eliminate the cube root in the numerator. This is done by multiplying the numerator and the denominator by a term that makes the expression a perfect cube.
02
Determine the Rationalizing Factor
Since the numerator is \(\sqrt[3]{5 y^2}\), to make it a perfect cube, we need another factor of \(5y^2\). Therefore, the rationalizing factor is \(5^{2/3} y^{4/3}\).
03
Multiply to Eliminate the Cube Root
Multiply both the numerator and the denominator by \(\sqrt[3]{25 y^4}\) (which is the decimal representation of \((5y^2)^{2/3}\)): \[\frac{\sqrt[3]{5 y^2} \cdot \sqrt[3]{25 y^4}}{\sqrt[3]{4 x} \cdot \sqrt[3]{25 y^4}}\] This simplifies to \[\frac{\sqrt[3]{(5 y^2)^3}}{\sqrt[3]{100 x y^4}}\]
04
Simplify the Expression
The cube root of the numerator, where the expression is \((5y^2)^3\), becomes \(5y^2\). Therefore, the numerator simplifies to 5y^2. The denominator becomes \(\sqrt[3]{100x y^4}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Rationalization Process
Rationalization is a technique used in mathematics to simplify expressions involving roots. In our problem, this involves removing the cube root from the numerator.
- This is done by multiplying both the numerator and denominator by a strategic value, called the rationalizing factor.
- By making the numerator a perfect cube, we eliminate the root without altering the overall value of the fraction.
Cube Roots
A cube root asks what number, multiplied by itself three times, gives us the original value.
- For instance, the cube root of 8 is 2, because 2 multiplied by itself thrice is 8.
- In cube root expressions, we often need to adjust them to reach a simpler form.
Mathematical Expressions
Mathematical expressions like the one given in the problem can at first seem a bit daunting, but they are simply representations of numbers and operations performed on them.
- In our particular case, \(\frac{\sqrt[3]{5y^2}}{\sqrt[3]{4x}}\), we have a division of two cube root expressions.
- Understanding these expressions requires knowing the interplay of numbers, roots, and operations.
Multiplying Rational Expressions
Multiplying rational expressions is a key part of the rationalization process.
- This involves combining fractions by multiplying both numerators and denominators.
- Let's consider our example: we multiply the expression by \(\sqrt[3]{25y^4}\) on both top and bottom.