Section 1 Part 1 Chapter 5
1
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Objectives
2
6
5
3
4
Integer Exponents – Part 1
Use the product rule for exponents.
Define 0 and negative exponents.
Use the quotient rule for exponents.
5.1
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We use exponents to write products of repeated factors. For example,
25 is defined as 2 • 2 • 2 • 2 • 2 = 32.
The number 5, the exponent, shows that the base 2 appears as a factor five times. The quantity 25 is called an exponential or a power. We read 25 as “2 to the fifth power” or “2 to the fifth.”
Integer Exponents
Slide 5.1- 3
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Use the product rule for exponents.
Objective 1
Slide 5.1- 4
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Product Rule for ExponentsIf m and n are natural numbers and a is any real number, then
am • an = am + n.
That is, when multiplying powers of like bases, keep the same base and add the exponents.
Slide 5.1- 5
Use the product rule for exponents.
Be careful not to multiply the bases. Keep the same base and add the exponents.
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Apply the product rule, if possible, in each case.
a) m8 • m6
b) m5 • p4
c) (–5p4) (–9p5)
d) (–3x2y3) (7xy4)
= m8+6 = m14
Cannot be simplified further because the bases m and p are not the same. The product rule does not apply.
= 45p9 = (–5)(–9)(p4p5) = 45p4+5
= –21x3y7 = (–3)(7) x2xy3y4 = –21x2+1y3+4
Slide 5.1- 6
CLASSROOM EXAMPLE 1
Using the Product Rule for Exponents
Solution:
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Define 0 and negative exponents.
Objective 2
Slide 5.1- 7
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Zero ExponentIf a is any nonzero real number, then
a0 = 1.
Slide 5.1- 8
Define 0 and negative exponents.
The expression 00 is undefined.
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Evaluate.
290
(–29)0
–290
80 – 150
= 1
= 1
= – (290) = –1
= 1 – 1 = 0
Slide 5.1- 9
CLASSROOM EXAMPLE 2
Using 0 as an Exponent
Solution:
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Negative Exponent
For any natural number n and any nonzero real number a,
1 .nn
aa
A negative exponent does not indicate a negative number; negative exponents lead to reciprocals.
22
1 13 Not negative
3 9
22
1 13 Negati
9v
3e
Slide 5.1- 10
Define 0 and negative exponents.
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Write with only positive exponents.
6-5
(2x)-4 , x ≠ 0
–7p-4, p ≠ 0
Evaluate 4-1 – 2-1.
5
1
6
4
1, 0
2x
x
4
17p
4
7, 0p
p
1 1
4 2
1 2
4 4 1
4
Slide 5.1- 11
CLASSROOM EXAMPLE 3
Using Negative Exponents
Solution:
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Evaluate.
3
1
4
3
1319
3
114
3
11
4
341
1 34 64
3
1
3
9
3
1 1
3 9
3
1 9
3 1
1 9
27 1
9
27
1
3
Slide 5.1- 12
CLASSROOM EXAMPLE 4
Using Negative Exponents
Solution:
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Special Rules for Negative Exponents
If a ≠ 0 and b ≠ 0 , then
and1 nna
a
.n m
m n
a b
b a
Slide 5.1- 13
Define 0 and negative exponents.
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Use the quotient rule for exponents.
Objective 3
Slide 5.1- 14
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Quotient Rule for Exponents
If a is any nonzero real number and m and n are integers, then
That is, when dividing powers of like bases, keep the same base and subtract the exponent of the denominator from the exponent of the numerator.
.m
m nn
aa
a
Slide 5.1- 15
Use the quotient rule for exponents.
Be careful when working with quotients that involve negative exponents in the denominator. Write the numerator exponent, then a subtraction symbol, and then the denominator exponent. Use parentheses.
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Apply the quotient rule, if possible, and write each result with only positive exponents.
8
13
m
m
6
8
5
5
8 13 55
1, 0m m m
m
6 ( 8) 6 8 25 5 5 , or 25
3
5, 0
xy
y Cannot be simplified because the bases x and y are
different. The quotient rule does not apply.
Slide 5.1- 16
CLASSROOM EXAMPLE 5
Using the Quotient Rule for Exponents
Solution: