15.1 – Introduction to Radicals

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15.1 – Introduction to Radicals Radical Expressions Finding a root of a number is the inverse operation of raising a number to a power. This symbol is the radical or the radical s n a inde x radical sign radica nd The expression under the radical sign is the radicand. The index defines the root to be taken.

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15.1 – Introduction to Radicals. Radical Expressions. Finding a root of a number is the inverse operation of raising a number to a power. radical sign. index. radicand. This symbol is the radical or the radical sign. The expression under the radical sign is the radicand. - PowerPoint PPT Presentation

Transcript of 15.1 – Introduction to Radicals

Page 1: 15.1 – Introduction to Radicals

15.1 – Introduction to RadicalsRadical Expressions

Finding a root of a number is the inverse operation of raising a number to a power.

This symbol is the radical or the radical sign

n aindex

radical sign

radicand

The expression under the radical sign is the radicand.

The index defines the root to be taken.

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Square Roots

If a is a positive number, then

a is the positive square root of a and

100

a is the negative square root of a.

A square root of any positive number has two roots – one is positive and the other is negative.

Examples:

10

25

49

5

7

11 36 6

9 non-real #

15.1 – Introduction to Radicals

81.0 9.0

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What does the following symbol represent?

The symbol represents the positive or principal root of a number.

15.1 – Introduction to Radicals

4 5xyWhat is the radicand of the expression ?

5xy

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What does the following symbol represent?

The symbol represents the negative root of a number.

15.1 – Introduction to Radicals

3 525 yxWhat is the index of the expression ?

3

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Cube Roots

3 27

A cube root of any positive number is positive.

Examples:

3 5

43

125

64

3 8 2

A cube root of any negative number is negative.

3 a

15.1 – Introduction to Radicals

3 27 3 3 8 2

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nth Roots

An nth root of any number a is a number whose nth power is a.

Examples:

2

4 81 3

4 16

5 32 2

43 81

42 16

52 32

15.1 – Introduction to Radicals

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nth Roots

4 16

An nth root of any number a is a number whose nth power is a.

Examples:

15 1

Non-real number

6 1 Non-real number

3 27 3

15.1 – Introduction to Radicals

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Radicals with Variables

8z

Examples:

123 8y

20x 64x

9 243 64x y 3 84x y

4z 10x 32x

42y

26x 12x 53y 15y 33 7x y 9 21x y

15.1 – Introduction to Radicals

12x 6x 5 15y 3y 3 219 yx 73yx

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15.2 – Simplifying RadicalsSimplifying Radicals using the Product Rule

40

Examples:

18

700

4 10

9 2

100 7

If and are real numbers, then a ba b a b

Product Rule for Square Roots

2 10

3 2

10 7

15 157 75 7 25 3 7 5 3 35 3

104

29

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Simplifying Radicals using the Quotient Rule

16

81

Examples:

2

5

4

9

aIf and are real numbers and 0, then

b

aa b b

b

Quotient Rule for Square Roots

2

25

9 5

7

3 5

7

16

81

2

25

45

49

15.2 – Simplifying Radicals

49

45

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Simplifying Radicals Containing Variables

11x

Examples:

8

27

x

67

25

y y

3 7

5

y y

10x x 5x x

418x 49 2x 23 2x

8

9 3

x

4

3 3

x8

27

x

15.2 – Simplifying Radicals

25

7 7y

25

7 7y

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Simplifying Cube Roots

3 88

Examples:

381

8

310

27

3

3

81

8

3 27 3

2

3 8 11 32 11

3 50 3 50

3 10

3

3

3

10

27

33 3

2

15.2 – Simplifying Radicals

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3 3 727m n

Examples:

3 3 63 m n n

2 33mn n

15.2 – Simplifying Radicals

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Examples:

12 4 185 64x y z

10 2 4 15 35 32 2x x y z z

2 3 2 4 352 2x z x y z

15.2 – Simplifying Radicals

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5 3x x

Review and Examples:

6 11 9 11

8x

15 11

12 7y y 5y

7 3 7 2 7

15.3 – Adding and Subtracting Radicals

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27 75

Simplifying Radicals Prior to Adding or Subtracting

3 20 7 45

9 3 25 3

3 4 5 7 9 5

3 3 5 3 8 3

3 2 5 7 3 5

6 5 21 5 15 5

36 48 4 3 9 6 16 3 4 3 3

6 4 3 4 3 3 3 8 3

15.3 – Adding and Subtracting Radicals

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4 3 39 36x x x

Simplifying Radicals Prior to Adding or Subtracting

6 63 310 81 24p p

2 2 23 6x x x x x

23 6x x x x x 23 5x x x

6 63 310 27 3 8 3p p

2 23 310 3 3 2 3p p 2 328 3p

2 23 330 3 2 3p p

15.3 – Adding and Subtracting Radicals