Scientific Notation and 7.6 Quiz Study Guide

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CP Algebra I

Name: ________________________________________

SCIENTIFIC NOTATION & EXPONENTIAL FUNCTIONS STUDY GUIDE

A. KNOW HOW TO CONVERT A NUMBER INTO SCIENTIFIC NOTATION

Step 1: Determine where the decimal point is in the number

Step 2: Determine where would you put the decimal to make this number be between 1 and 10

Step 3: Decide how many decimal places you need to move the decimal

Step 4: Write the new decimal

× 10 𝑛 , 𝑛 =

# of places*

*Note: + if the original number is more than 1, the exponent is positive

- if the original number is less than 1, the exponent is negative

Example: To write 527 in scientific notation, place the decimal point at end of number and move left n decimal places so that the number is between 1 and 10. This would give

5.27x10

n . Since the original number is more than 1 (527>1), the exponent is positive and since we moved 2 decimal places to the left, we get a final answer of

5.27x10

2 .

B. KNOW HOW TO CONVERT A NUMBER INTO STANDARD FORM

Step 1:

Move the decimal point to the right for positive exponents of 10.

Move the decimal point to the left for negative exponents of 10.

The exponent tells you how many places to move.

Step 2: Fill in with zeros

Example: To write

5.43x10

-

3 in standard form, move the decimal left (since exponent is negative) 3 places and fill in with zeros. We get a final answer of .00543.

C. KNOW HOW TO MULTIPLY IN SCIENTIFIC NOTATION i) Multiplying by a number

Step 1: Multiply the number times the coefficient

Step 2: Simplify so that the number is written in correct scientific notation

Example: To multiply 5(

4.13x10

3 ), multiply the 5 x 4.13 to get

20.65 correctly in scientific notation so your answer is

2.065x10

20.65x10

4 .

3 . Now write the ii) Multiplying two numbers in scientific notation

Step 1: Multiply the coefficients

Step 2: Add the exponents

Step 3: Make sure your final answer is written in proper scientific notation

Example: To multiply (

7x10

2 )(

4x10

5 ), multiply the 7 x 4 and add the exponents 2 & 5 to get

28x10

7

.

Now write the 28 correctly in scientific notation so your answer is 2.8x10

8 .

D. KNOW HOW TO DIVIDE NUMBERS IN SCIENTIFIC NOTATION

Step 1: Divide the coefficients

Step 2: Subtract the exponents

Step 3: Make sure your final answer is written in proper scientific notation

95.2x10

-

2

Example: To divide

7x10

7

, first divide 95.2 and 7 to get 13.6. Then subtract the exponents (-

2 – 7) to get -9. This becomes 13.6𝑥10 −9 . And, finally write answer in proper scientific notation to get 1.36x10

-

8

.

E. KNOW HOW TO ORDER NUMBERS IN SCIENTIFIC NOTATION

Step 1: Write every number in correct scientific notation

Step 2: Order each by exponent first and then by coefficient

Example: To order

9.25x10

-

5

,10.8x10

-

3

, and 0.013 from least to greatest, write each number in correct scientific notation. This gives 9.25x10

-

5

,1.08x10

first by exponent then by coefficient. Final answer is

-

2

, and 1.03x10

-

2

9.25x10

-

5

F. KNOW HOW TO EVALUATE AN EXPONENTIAL FUNCTION

Step 1: Plug in the values of the variable and solve.

,1.03x10

-

2

. Now order the numbers

, and 1.08x10

-

2

Example: Evaluate the exponential function, f(x)

=

3 x for x = –2, –1, 0, 1, and 2 . f(

-

2)

=

3

-

2 =

1

3

2

=

1

9 f(0)

=

3

0 =

1 f(2)

=

3

2 =

9 f(

-

1)

=

3

-

1 =

1

=

1 f(1)

=

3

1

=

3

3

1

3

G. KNOW HOW TO GRAPH AN EXPONENTIAL FUNCTION USING A TABLE

Step 1: Plug in the values of the variable and solve.

Step 2: Plot each point and draw curve. Remember the curve will get very close to zero on the left side.

Example:

H. KNOW HOW TO DETERMINE IF A RULE REPRESENTS AN EXPONENTIAL FUNCTION

With a table of values, you first make sure the change in x is constant. Then you look at the ratio of the y's value. If the ratio of the values is the same, then it is an exponential function.

Example: Does the table represent a linear or exponential function?

1

2

120

180

180/120 = 1.5, 270/180 = 1.5, 405/270 = 1.5

Therefore, this is an exponential function.

5 607.5

6 911.25

With a function rule, if the x is not an exponent, then it is a linear function. If the x is an exponent, then it is an exponential function

Example: Does the rule represent a linear or exponential function? a) y = 2 x - 3 This is linear because the exponent on x is one. b) Y = 3 x + 4 is exponential because the variable x is an exponent.

PRACTICE

A. Write each number in scientific notation.

1. 890,000,090 ____________________

2. 605,000 ____________________

3. 706,079 ____________________

4. 1,108.4 ____________________

5. 0 .001234 ____________________

B. Write in standard form.

6. 8.3x10

5 ____________________

7. 9.43x10

4

____________________

8. 7.002x10

-

2

____________________

C. Multiply. Write your answer in correct scientific notation.

9. (4.5x10

-

14

)(5.2x10

3

) ____________________

10. (6.1x10

5

)(1.2x10

-

3

) ____________________

11. 1.3(8.102x10

6

) ____________________

12. 8.5(9.32x10

5

) ____________________

D. Divide. Write your answer in correct scientific notation.

13.

(7.2x10

4

)

(9.4x10

-

11

)

____________________

14.

(3.04x10

5

)

(9.89x10

2

)

____________________

E. Order from least to greatest. Write numbers in correct scientific notation, then order the numbers.

15.

7.235x10

7

,8.6x10

6

, and 8,900,000 _________________________________________

16. 1.03x10

9

, 2.8x10

7

, and 1,035,000,000 ______________________________________

0

1

2

F. Evaluate each exponential function.

17.

f(x)

=

2

·

4 x

for x = –2, –1, 0, 1

18.

f(x)

=

5 x for x = –2, –1, 0, 1

G. Evaluate each exponential function.

19.

Graph 𝑦 = 2 ∙ 4 𝑥

using the table below.

x 2 ∙ 4 𝑥 (x, y)

-2

-1

H. Does the rule or table represent a linear or exponential function? Explain.

20.

𝑦 = 2𝑥

21. x 0 1 2 3 f(x) -6 -1 4 9

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