Avon High School Section: P.2 ACE COLLEGE ALGEBRA II - NOTES Exponents and Scientific Notation Mr. Record: Room ALC-129 Day 2 The Product and Quotient Rules for Exponents The U.S. National Debt as of June 8, 2012 is shown in the box to the right. Just how big is this number? How much would each citizen of the U.S. have to pay to eliminate this debt? The Product Rule for Exponents bm bn bmn When multiplying exponential expressions with the same base, add the exponents. Use this sum as the exponents of the common base. The Quotient Rule for Exponents bm bmn , b 0 bn When dividing exponential expressions with the same nonzero base, subtract the exponent in the denominator from the exponent in the numerator. Use this difference as the exponents of the common base. Multiply or divide each expression using the appropriate rule. Example 1 a. (4 x3 y 4 )(10 x 2 y8 ) b. 27 x14 y8 3x3 y 5 Zero as an Exponents and Negative Integers as Exponents The Zero Exponent Rule If b is any real number other than 0, b0 1 The Negative-Exponent Rule If b is any real number other than 0, and n is a natural number, then 1 bn n b Investigation: Consider the expression below and use two different methods to deduce that it is equivalent to 1. x7 x7 Example 2 a. 5 2 Rewrite each expression with positive exponents. b. (3) 3 c. 1 4 2 d. 3x 6 y 4 Three Other Rules for Exponents The Power Rule for Exponents b m n b m n When an exponential expression is raised to a power, multiply the exponents. Place the product of the exponents on the base and remove the parentheses. The Products-toPowers Rule for Exponents n ab a nb n When a product is raised to a power, raise each factor to that power. The Quotients-toPowers Rule for Exponents n a a n , b0 b b When a quotient is raised to a power, raise each part of the fraction to that power. n Simplifying Exponential Expressions Properties of exponents are used to simplify exponential expressions. An expression is simplified when 1. 2. 3. 4. Example 3 3 a. 2x y Simplify. 6 4 b. 6 x y 2 5 3xy 3 100 x12 y 2 c. 20 x16 y 4 5x d. 4 y 2 Scientific Notation Sometimes it is much more convenient to write very large (or very small) numbers in scientific notation. Scientific Notation Form A number is written in scientific notation form when it is expressed as a 10n Where the absolute value of a is greater than or equal to 1 and less than 10 1 a 10 , and n is an integer. How would you write the U.S. National Debt from June 8, 2012 in scientific notation? Perform the indicated computations, writing each answer in Example 4 scientific notation for parts a and b. 1.2 106 a. 7.1105 5 107 b. 3 10 3 Names of Large Numbers 10 2 hundred 103 thousand 106 million 109 1012 billion 1015 quadrillion 1018 quintillion 10 21 1024 sextillion 1027 octillion 1030 nonillion 10100 10googol googol trillion septillion googolplex c. Pell Grants help low-income undergraduate students pay for college. In 2006, the federal cost of this program was $13 billion and there were 5.1 million grant recipients. How much to the nearest hundred dollars was the average grant?