Department of Mathematics |
Basic Algebra by Example Series |
Key Concept: Learn the many form of radicals so as to be able to manipulate it to aid in the simplification of mathematical computations.
Skills to Learn
1. Learn how convert between Rational Exponents and Radicals
2. Know the basic properties of Radicals
3. Know how to simplify Radicals
4. Know how to compute the sum and difference of Radicals
5. Know how to compute the product of Radicals
6. Know how to rationalize the denominator (removed radicals)
Conversion Between Rational Exponents and Radicals
, stated as the n-th root of b
Examples: (1) , the square root of 13 or (2) , the 4-th root of a or |
Rational Exponent | Radical |
(1) | |
(2) | |
(3) | |
(4) , not a real number | , not a real number |
(5) | |
(6) | |
(7) | |
(8) | |
(9) |
Properties of Radicals
Properties | Examples
|
(a)
(b) |
|
(a) (b) |
|
|
(a) (b) |
Simplifying Radicals
Strategy: remove as many terms from the radical and eliminate the radical is possible.
Example 10. Simplify
Strategy: look for cube root factors and remove from radical
Solution is
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Example 11. Simplify Strategy: group terms under radical and find and remove square root factor(s) from radical Remember:
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Example 12. Simplify Strategy: look for cube root factors and remove from radical
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Example 13. Simplify Strategy: look for 5-th root factors and remove radical
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Sums and Differences
Strategy: Combine / group like terms and evaluate
Example 14. Simplify Strategy: Group terms.
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Example 15. Simplify Strategy: group like terms
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Multiplication and Divisions
Strategy: Multiply or divide like terms and simplify
Example 16. Simplify Strategy: Expand via multiplication radicals.
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Example 17. Simplify Strategy: Expand keeping terms together
So |
Example 18. Simplify Strategy: Expand keeping terms together So
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Example 19. Simplify
Strategy: Expand keeping terms together
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Rationalizing the Denominator
Strategy - Eliminate the radical from the denominator by multiplying
both the numerator and denominator by a suitable
factor that will leave the denominator free of radicals.
Remember:
or
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Example (note
)
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45 |
Examples of Rationalizing Denominator
Example 20. Rationalize
denominator for
Strategy: multiply numerator and denominator by
So |
Example 21. Rationalize
denominator for
Strategy: multiply numerator and denominator by
So |
Example 22. Rationalize denominator for Strategy: rationalize with
So |
Example 23. Rationalize denominator for , If a = 1 and Strategy: rationalize with Note: If Then:
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