Math 2 Lesson 1-4: Zero & Negative Exponents Name ______________________________ Date ____________________________ Learning Goal: I can use exponent rules to simplify expressions with exponents of zero and negative exponents. The pond at North Chagrin Reservation fills up with lily pads every year. Lily pads reproduce rapidly, doubling in population every day! Suppose you go the pond today (day zero) and count 32 lily pads. A week later, you return to find 4096 lily pads! 1. Fill in the following table to illustrate the growth of the lily pads. Day Number of Lily Pads Value written as a power of 2. -4 four days ago -3 -2 -1 0 today 1 tomorrow 2 32 64 32 21 32 2 2 3 4 5 6 7 one week from today 4096 32 2 7 2. What happened to the lily pad population as time moved forward? 3. What happened to the lily pad population as time moved backward? 4. What happened when the exponent was 0? 5. What happened when the exponent was negative? OVER Page 2 6. Let’s see what happens when we raise other numbers (bases) to the power of 0. 50 _____ 61160 _____ 2 x 0 _____ Just for fun….. What do you think 0 0 _____ 0 _____ (0)0 equals? _________ ZERO POWER PROPERTY: When b is any base and b 0 , 8. 89 _____ b0 _____ Use your calculator to evaluate the following. 21 _____ 22 _____ 23 _____ 24 _____ 23 _____ 24 _____ Answer the following using fractions only! 21 _____ 22 _____ How are the numbers with the positive exponents related to those of the negative exponents? 9. What happens when we raise other numbers (bases) to negative exponents. Write your answers as simplified fractions. 31 _____ 10. 43 _____ 53 _____ Let’s convert our answers from above to fractions with positive exponents. Fill in the blanks. 31 1 3 11. 82 _____ 82 1 43 8 1 5 3 5 4 One conclusion we can draw about negative exponents is… NEGATIVE EXPONENT PROPERTY: When b is any base and b 0 then b x 1 1 b Page 3 12. Simplify the following using properties discovered in Lesson 1-3. Write your answers as simplified fractions. 1 2 4 5 13. ______________ 4 5 3 4 5 ______________ 4 ______________ 4 5 ______________ Simplify the following. Write your answers as simplified fractions. 1 4 5 2 ______________ 4 5 3 4 4 5 ______________ ______________ 4 5 ______________ How are the numbers with the positive exponents related to those of the negative exponents? 14. Let’s convert our answers from above to fractions with positive exponents. Fill in the blanks. 1 5 4 5 4 15. 2 3 5 4 5 4 4 5 4 5 4 5 4 5 4 The other conclusion we can draw about negative exponents is… NEGATIVE EXPONENTS PROPERTY: When a and b are not equal to zero, 16. a b x b a Simplify the following. Use only positive exponents in your answers. 1 x y 2 2 ______________ a b ______________ 5x 7y 3 ______________ 2h j ______________ OVER Homework: Simplify completely. Leave your answers as fractions. No negative exponents! 1. 5 3 2. 7 2 3. 6 1 4. b 7 5. 2 5 6. 3 2 7. a b 8. x 2y 9. 19 0 10. 7 11. y0 12. abcdefg 1 4 3 8 13. = 0 0 0 -1 14. = = 15. True or False: A positive number raised to a negative power will equal a negative number when simplified. Explain your answer. What if a negative exponent appears in the bottom of a fraction? 1 23 2 3 1 1 x5 x 5 1 4 b 4 c 4 b 4 4 c b c Simply put, if you get a base with a negative exponent in the denominator, move it to the numerator with a positive exponent. Simplify completely. Leave your answers as fractions. No negative exponents! 16. 1 y 6 17. 1 8 3 18. x 7 y 5 19. 23 w6 x 4 y 5 z 2 Page 4