Chapter 11: Problem 50
Write each expression in simplest radical form. If \(a\) radical appears in the denominator, rationalize the denominator. \(\sqrt{98 x^{6} y^{-7}}\)
Short Answer
Expert verified
The simplest radical form is \( \frac{7x^3 \sqrt{2y}}{y^4} \).
Step by step solution
01
Simplify the Radicand
Start by simplifying the expression inside the square root: \( \sqrt{98x^6y^{-7}} \). Break down the components: 98 can be factored into \( 2 \times 49 \) and 49 is a perfect square (\( 7^2 \)). The expression becomes \( \sqrt{2 \times 7^2 \times (x^6) \times (y^{-7})} \).
02
Simplify the Squared Terms
Extract the square terms from the square root. \( 7^2 \) simplifies to 7 outside the root, and \( x^6 \) becomes \( x^3 \) because \( x^6 = (x^3)^2 \). The expression is now \( 7x^3\sqrt{2y^{-7}} \).
03
Simplify the Negative Exponent
Convert the negative exponent by using the property \( y^{-7} = \frac{1}{y^7} \). The expression inside the square root becomes \( \sqrt{\frac{2}{y^7}} = \frac{\sqrt{2}}{\sqrt{y^7}} \).
04
Rationalize the Denominator
To simplify \( \frac{\sqrt{2}}{\sqrt{y^7}} \), rationalize the denominator. Rewrite \( \sqrt{y^7} \) as \( y^3 \sqrt{y} \), so \( \frac{\sqrt{2}}{y^3 \sqrt{y}} \). Multiply numerator and denominator by \( \sqrt{y} \) to get \( \frac{\sqrt{2y}}{y^4} \).
05
Combine the Terms
Finally, combine the terms outside and inside the radical. The result is \( \frac{7x^3 \sqrt{2y}}{y^4} \). This is the expression in its simplest radical form.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Rationalize the Denominator
Rationalizing the denominator involves eliminating any radicals from the bottom of a fraction. This process is crucial because it is often seen as a standard way to present a fraction, making it easier to understand and work with. To rationalize a denominator like \( \frac{\sqrt{2}}{y^3 \sqrt{y}} \), which has a radical in it, you multiply both the numerator and the denominator by the same radical that will help remove it. In this case, multiplying by \( \sqrt{y} \) transforms the expression to \( \frac{\sqrt{2y}}{y^4} \).
- Multiply both the top and bottom by the same square root.
- This should result in a rational number in the denominator.
Negative Exponents
A negative exponent indicates taking the reciprocal of a base raised to a positive exponent. This can be confusing initially, but with some practice becomes an intuitive part of algebra. For example, the expression \( y^{-7} \) is equivalent to \( \frac{1}{y^7} \). This is because any base with a negative exponent can be rewritten as a fraction:
- Positive Exponents: \( a^3 \)
- Negative Exponents: \( a^{-3} = \frac{1}{a^3} \)
Perfect Squares
Perfect squares are numbers or expressions that can be written as the square of another number or expression. Recognizing perfect squares can be a huge time saver when simplifying radical expressions.Understanding them makes it straightforward to determine what can be pulled out of a radical. For instance, in the expression \( 49 \), because \( 49 = 7^2 \), we can directly take 7 out of the radical. Similarly, if you have \( x^6 = (x^3)^2 \), you can simplify this to \( x^3 \) outside the square root as well.
- A perfect square provides a whole number when taken as a square root.
- Identifying them speeds up simplification processes.
Square Root Simplification
To simplify a square root, break down the number or expression inside into its prime factors or identifiable components. This is done to separate the perfect squares from the rest.Take \( \sqrt{98x^6y^{-7}} \), for instance. By expressing 98 as \( 2 \times 49 \), and recognizing \( 49 \) as a perfect square, you simplify it to \( 7 \) outside the radical. Similarly, split \( x^6 \) into \( (x^3)^2 \) to get \( x^3 \) out.
- Identify the factors within the radical.
- Extract perfect squares.
- Reconstruct the expression to its simplest form.