5.6 Rules of Exponents and Scientific Notation

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Chipola College

MGF 1107

5.6 Rules of Exponents and Scientific Notation

A. Negative powers indicate reciprocals. Simplify the following.

1. 2

-3

4. 5

-2

=

=

1

2

3

1

8

2. 3

-3

= 3. 4

-2

=

5. 8

-1

= 6. 1

3

3

B. A power equal to zero indicates a value of 1 . Evaluate. Ex. 8 0 = 1; -6y 0 = -6

1

 

6

1. 4

0

= 2. 8

0

= 3. 3x

0

= 4. -5

0

=

C. To multiply exponential expressions add the exponents. Multiply expressions.

1. 3

3 

3

7 

2. 5

-4

(5) = 3. 2

3 

2

2

D. To divide exponential expressions subtract the exponents. Note – you may want to write the expression

using positive exponents first. Divide the following expressions.

1.

6

5

6

3

 2.

8

9

E. To raise an exponential expression to a power multiply the exponents. Ex.

 

3  x

12

You Try:

1. (7

3

)

4

=

4. (5

-3

)

2

=

2. (3

5

)

2

=

5. (-2)

4

3. (3

-4

)

-5

=

6. (-345

72

)

0

2 a. - 3

2

b. (-3)

2 c.

3

4 d. (2

2

)

-3

e.

7

7

3 f. 4

5 

4

3

Scientific Notation

Often scientific problems deal with very large and very small numbers. Thus, we need a “shorter” way to write them. Very small numbers are written using negative exponents. Very large numbers are written using positive exponents.

1.

Write the following numbers in scientific notation.

______________ a. half-life of lead 14,000,000,000,000,000,000 yrs

______________ b. mass of earth 5,980,000,000,000,000,000,000,000 kgs

______________ c. wavelength of yellow-green light .0000006 meters

______________ d. mass of hydrogen .000 000 000 000 000 000 001 067 g

2.

Convert the following into standard or decimal notation.

_______________ a. 7.84 X 10

5

_______________________ b. 5.3 X 10

-3

________________ c. 6 X 10

-6

________________ e. 4.58 X 10

2

_______________________ d. 2 X 10

6

________________________f. 3.7 X 10

-1

You Try:

Fill in the blanks. STANDARD

5230000

__________

__________

SCIENTIFIC

__________

7.82 X 10

-4

4.367 X 10

3

.00000078 __________

___________

.0249

6.55 X 10

___________

__________ 2 X 10

5

__________ 7 X 10

-5

Multiplying and Dividing using Scientific Notation

Multiply or divide. Write your answers in standard notation and scientific notation.

1. (3 X 10 4 )(2 X 10 2 ) 2. (1.2 X 10 -7 )(3.1 X 10 2 )

3.

7 .

8 X 10

9

4 X 10

3

4.

5 .

6 X 10

4

2 .

5 X 10

3

5. (0.000041)(3000) 6. 0 .

0000000000 48

24 , 000 , 000 , 000

You Try: a. (4 X 10

3

)(7 X 10

5

)

3 X 10

8 c.

6 X 10

12 b. (3.2 X 10

-7

)(4 X 10

3

) d.

3 .

2 X 10

5

8 .

0 X 10

8

e. (0.000041)(3000) f.

20 , 000

0 .

0005

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