Section 2-8Section 2-8

DefinitionsDefinitions

Square rootSquare root: = 6.: = 6.

Radical signRadical sign: This is a radical sign. : This is a radical sign.

Perfect squarePerfect square: 4, 9, 16, 25, … are : 4, 9, 16, 25, … are perfect square numbers. Because 2*2=4,perfect square numbers. Because 2*2=4,

3*3=9, 4*4=16, 5*5=25, …3*3=9, 4*4=16, 5*5=25, …

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Section 2-8 definitions cont.Section 2-8 definitions cont.Irrational numberIrrational number: is a number that cannot be : is a number that cannot be expressed in the form of which is a fraction.expressed in the form of which is a fraction.

Example: = 10.95445115…, since this is not Example: = 10.95445115…, since this is not a repeating or terminating decimal, this number a repeating or terminating decimal, this number is irrational.is irrational.

Real numbersReal numbers: are the set of rational and the : are the set of rational and the set of irrational numbers together.set of irrational numbers together.

See whiteboard Venn diagramSee whiteboard Venn diagram

a

b

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Section 2-8 examplesSection 2-8 examplesFind the following square roots:Find the following square roots:

1.) 2.) - 3.) 1.) 2.) - 3.) Answers: 1.) 4 2.) -7 3.) 11Answers: 1.) 4 2.) -7 3.) 11

Name the set or sets of numbers which eachName the set or sets of numbers which eachnumber belongs to. Use N for natural numbers,number belongs to. Use N for natural numbers,W for whole numbers, Z for integers, Q for rationalW for whole numbers, Z for integers, Q for rationalNumbers, and I for irrational numbers.Numbers, and I for irrational numbers.

4.) - 5.) 0 6.) 8/44.) - 5.) 0 6.) 8/4 Answers: 4.) Z, Q 5.) W, Z, Q 6.) N, W, Z, QAnswers: 4.) Z, Q 5.) W, Z, Q 6.) N, W, Z, Q

16 49 121

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