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0.3 (b) Radicals

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

Example 11. Simplify

Strategy: group terms under radical and find and remove square root factor(s) from radical

Remember:

Example 12. Simplify

Strategy: look for cube root factors and remove from radical

Example 13. Simplify

Strategy: look for 5-th root factors and remove radical

Sums and Differences

Strategy: Combine / group like terms and evaluate

Example 14. Simplify

Strategy: Group terms.

Example 15. Simplify

Strategy: group like terms

Multiplication and Divisions

Strategy: Multiply or divide like terms and simplify

Example 16. Simplify

Strategy: Expand via multiplication radicals.

Example 17. Simplify

Strategy: Expand keeping terms together

So

Example 18. Simplify

Strategy: Expand keeping terms together

So

Example 19. Simplify

Strategy: Expand keeping terms together

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

Example (note )

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: