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Math 9: Laws of Exponents. Products of Exponents Quotients of Exponents Negative Exponents Evaluating Exponents Scientific Notation. 1. Products of Exponents. We know that 5 3 = 5∙5∙5 So, 5 3 ∙ 5 4 = 5 ∙5∙5 ∙ 5∙5∙5∙5 5 3 ∙ 5 4 = 5 7
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Math 9: Laws of Exponents Products of Exponents Quotients of Exponents Negative Exponents Evaluating Exponents Scientific Notation
1. Products of Exponents • We know that 53= 5∙5∙5 • So, 53∙ 54 = 5∙5∙5 ∙ 5∙5∙5∙5 • 53∙ 54 = 57 • Do you see a relationship between 53∙ 54 and 57?
Exponent Law #1 For any real numbers a, m, and n:
Practice Problems Now do practice problems 1 through 4 on your handout. We will go over them when you are done.
Now, go a step further… what happens if we have ? That would mean: From Exponent Law #1 we know that,
Exponent Law #2 For any real numbers a, m, and n:
When there is a product raised to a power, raise each factor to the outside power. Example:
Exponent Law #3 For any real numbers a, b, k, and m:
Practice Problems • Now do practice problems 5 through 8 on your handout. • We will go over them when you are done.
Math 9: Laws of Exponents Products of Exponents Quotients of Exponents Negative Exponents Evaluating Exponents Scientific Notation
2. Dividing with exponents Do you see a relationship between and ?
Exponent Law #4 For any real numbers a, k, and m, where a ≠ 0: Note: the same base number in the numerator and denominator
Exponent Law #4 Corollary Any real number raised to the zero power is 1. and by Law #4 So,
Exponent Law #5 For any real numbers a, b, k, m and w: and
Practice Problems • Now do practice problems 9 through 11 on your handout. • We will go over them when you are done.
Math 9: Laws of Exponents Products of Exponents Quotients of Exponents Negative Exponents Evaluating Exponents Scientific Notation
3. Negative Exponents Consider and use Law #4. But what does mean?
Thus, Which leads us to the next exponent law…
Exponent Law #6 For any real numbers x, m, and k, where x ≠ 0: and However, this law comes with a warning….
CAUTION!! WARNING!! It is very easy to make mistakes! What is wrong with… ?
CAUTION!! WARNING!! Be careful with the minus sign… Not
CAUTION!! WARNING!! Another easy sign error… What’s wrong with…. ?
CAUTION!! WARNING!! Be careful with the negative signs… Not
Practice Problems • Now do practice problems 12 – 14 on your handout. • We will go over them when you are finished.
More Practice Problems • Now you can do practice problems 15 through 18 on your handout. • These problems will use all the Exponent Laws we have learned so far. • We will go over them when you are done.
Math 9: Laws of Exponents Products of Exponents Quotients of Exponents Negative Exponents Evaluating Exponents Scientific Notation
Consider this equation: Reduce the fraction: Divide both sides by 2: Now, what times itself 3 times equals 729? Thus, x = 9
Practice Problems • Now do practice problems 19 through 21 on your handout. • We will go over them when you are done.
Math 9: Laws of Exponents Products of Exponents Quotients of Exponents Negative Exponents Evaluating Exponents Scientific Notation
5. Scientific Notation • Used for very large & very small numbers. • Makes multiplying & dividing much easier. • Has this form: • Has 1 non-zero digit left of the decimal point. • Move the decimal point counting the moves. • Moving left means a positive exponent. • Moving right means a negative exponent.
Write 8,532,000 in scientific notation. • Locate the decimal point. • Move the decimal point. • Count number of places moved and direction. • Make the number of places moved the exponent. • Write the number.
Write 0.0000345 in scientific notation. • Locate the decimal point. • Move the decimal point. • Count the number of places moved and direction. • Make the number of places moved the exponent. • Write the number.
Multiplying and Dividing with scientific notation. • Consider : • Separate the decimals and powers of 10. • Multiply decimals and powers of 10 separately.
Another example: • Consider • Put numbers into scientific notation. • Separate decimals and powers of 10. Then multiply. WARNING!! THIS IS NOT SCIENTIFIC NOTATION!
Put 26.46 x into scientific notation. • Move the decimal counting places moved and direction. • Thus,
Practice Problems • Now do practice problems 22 through 27 on your handout. • We will go over them when you are done.
Review Lessons Worksheet • You are now ready to do the Worksheet for these lessons. • It is worth 20 points toward passing Math 9. • When is it due???