Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Rewrite radical expressions by using
rational exponents.
Simplify and evaluate radical expressions
and expressions containing rational
exponents.
Objectives
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
index
rational exponent
Vocabulary
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
The nth root of a real number a can be written as the
radical expression , where n is the index (plural:
indices) of the radical and a is the radicand. When a
number has more than one root, the radical sign
indicates only the principal, or positive, root.
n
When a radical sign shows no index, it represents a
square root. Even roots MUST be a positive Answer.
Reading Math
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
A rational exponent is an exponent that can be
expressed as , where m and n are integers and
n ≠ 0. Radical expressions can be written by using
rational exponents.
m
n
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Method 1 Evaluate
the root first.
(4)1
Write with a radical.
64
1
3
4
Evaluate the root.
Evaluate the power.
Check It Out! Example 3a
Write the expression in radical form, and
simplify.
Method 2 Evaluate
the power first.
Write will a radical.
4
Evaluate the power.
Evaluate the root.
( )
1
3
64 ( )1
3
64
3
64
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Method 1 Evaluate
the root first.
(2)5
Write with a radical.
4
5
2
32
Evaluate the root.
Evaluate the power.
Check It Out! Example 3b
Write the expression in radical form, and
simplify.
Method 2 Evaluate
the power first.
Write with a radical.
32
Evaluate the power.
Evaluate the root.
( )
5
2
4 ( )5
2
4
2
1024
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Write each expression by using rational
exponents.
Simplify.
a. b.
3
4
81
10
3
Check It Out! Example 4
9
3
10
1000
Simplify.
5
1
2
c.
2
4
5
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Method 1 Evaluate
the root first.
(5)3
Write with a radical.
625
3
4
125
Evaluate the root.
Evaluate the power.
Check It Out! Example 3c
Write the expression in radical form, and
simplify.
Method 2 Evaluate
the power first.
Write with a radical.
125
Evaluate the power.
Evaluate the root.
( )
3
4
625 ( )3
4
625
4
244,140,625
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Simplify the expression. Assume that all
variables are positive.
Check It Out! Example 2a
Product Property.
Simplify.
Factor into perfect fourths.
2  x
2x
4 4
16x
4
24 •
4
x4
4
24 •x4
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Find all real roots.
a. fourth roots of –256
A negative number has no real fourth roots.
Check It Out! Example 1
b. sixth roots of 1
A positive number has two real sixth roots.
Because 16
= 1 and (–1)6
= 1, the roots are 1
and –1.
c. cube roots of 125
A positive number has one real cube root.
Because (5)3
= 125, the root is 5.
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
When an expression contains a radical in the
denominator, you must rationalize the denominator. To
do so, rewrite the expression so that the denominator
contains no radicals.
Remember!
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
The properties of square roots in Lesson 1-3 also
apply to nth roots.
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Check It Out! Example 2b
Quotient Property.
Product Property.
Rationalize the numerator.
Simplify.
Simplify the expression. Assume that all
variables are positive.
8
4
4
3
x
4
2
27
3
x
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Check It Out! Example 2c
3 3
7 2
x x
Product Property of Roots.
Simplify.
Simplify the expression. Assume that all
variables are positive.
x3
3 9
x
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Rational exponents have the same properties as
integer exponents (See Lesson 1-5)
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Product of Powers.
Simplify each expression.
Simplify.
Evaluate the Power.
6
Check It Out! Example 5a
Check Enter the expression
in a graphing calculator.
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Simplify each expression.
(–8)
– 1
3
Check It Out! Example 5b
1
–8
1
3
1
2
–
Negative Exponent Property.
Evaluate the Power.
Check Enter the
expression in a graphing
calculator.
Holt Algebra 2
3-2 Radical Expressions and Rational Exponents
Quotient of Powers.
Simplify each expression.
Simplify.
Evaluate the power.
5
2
Check It Out! Example 5c
25
Check Enter the expression
in a graphing calculator.

3-2_radical_expressions_and_rational_exponents.ppt

  • 1.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Rewrite radical expressions by using rational exponents. Simplify and evaluate radical expressions and expressions containing rational exponents. Objectives
  • 2.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents index rational exponent Vocabulary
  • 3.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents The nth root of a real number a can be written as the radical expression , where n is the index (plural: indices) of the radical and a is the radicand. When a number has more than one root, the radical sign indicates only the principal, or positive, root. n When a radical sign shows no index, it represents a square root. Even roots MUST be a positive Answer. Reading Math
  • 4.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents A rational exponent is an exponent that can be expressed as , where m and n are integers and n ≠ 0. Radical expressions can be written by using rational exponents. m n
  • 5.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Method 1 Evaluate the root first. (4)1 Write with a radical. 64 1 3 4 Evaluate the root. Evaluate the power. Check It Out! Example 3a Write the expression in radical form, and simplify. Method 2 Evaluate the power first. Write will a radical. 4 Evaluate the power. Evaluate the root. ( ) 1 3 64 ( )1 3 64 3 64
  • 6.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Method 1 Evaluate the root first. (2)5 Write with a radical. 4 5 2 32 Evaluate the root. Evaluate the power. Check It Out! Example 3b Write the expression in radical form, and simplify. Method 2 Evaluate the power first. Write with a radical. 32 Evaluate the power. Evaluate the root. ( ) 5 2 4 ( )5 2 4 2 1024
  • 7.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Write each expression by using rational exponents. Simplify. a. b. 3 4 81 10 3 Check It Out! Example 4 9 3 10 1000 Simplify. 5 1 2 c. 2 4 5
  • 8.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Method 1 Evaluate the root first. (5)3 Write with a radical. 625 3 4 125 Evaluate the root. Evaluate the power. Check It Out! Example 3c Write the expression in radical form, and simplify. Method 2 Evaluate the power first. Write with a radical. 125 Evaluate the power. Evaluate the root. ( ) 3 4 625 ( )3 4 625 4 244,140,625
  • 9.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Simplify the expression. Assume that all variables are positive. Check It Out! Example 2a Product Property. Simplify. Factor into perfect fourths. 2  x 2x 4 4 16x 4 24 • 4 x4 4 24 •x4
  • 10.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Find all real roots. a. fourth roots of –256 A negative number has no real fourth roots. Check It Out! Example 1 b. sixth roots of 1 A positive number has two real sixth roots. Because 16 = 1 and (–1)6 = 1, the roots are 1 and –1. c. cube roots of 125 A positive number has one real cube root. Because (5)3 = 125, the root is 5.
  • 11.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents When an expression contains a radical in the denominator, you must rationalize the denominator. To do so, rewrite the expression so that the denominator contains no radicals. Remember!
  • 12.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents The properties of square roots in Lesson 1-3 also apply to nth roots.
  • 13.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents
  • 14.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Check It Out! Example 2b Quotient Property. Product Property. Rationalize the numerator. Simplify. Simplify the expression. Assume that all variables are positive. 8 4 4 3 x 4 2 27 3 x
  • 15.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Check It Out! Example 2c 3 3 7 2 x x Product Property of Roots. Simplify. Simplify the expression. Assume that all variables are positive. x3 3 9 x
  • 16.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Rational exponents have the same properties as integer exponents (See Lesson 1-5)
  • 17.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Product of Powers. Simplify each expression. Simplify. Evaluate the Power. 6 Check It Out! Example 5a Check Enter the expression in a graphing calculator.
  • 18.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Simplify each expression. (–8) – 1 3 Check It Out! Example 5b 1 –8 1 3 1 2 – Negative Exponent Property. Evaluate the Power. Check Enter the expression in a graphing calculator.
  • 19.
    Holt Algebra 2 3-2Radical Expressions and Rational Exponents Quotient of Powers. Simplify each expression. Simplify. Evaluate the power. 5 2 Check It Out! Example 5c 25 Check Enter the expression in a graphing calculator.