DefineandUseZeroandNegativeExponents83定义与使用零与负指数教学课件

1、8.3 Define and Use Zero and Negative ExponentsStudents will use zero and negative exponentsStudents will do assigned homework.Students will study vocabulary words.第1页，共20页。Lesson 8.3, For use with pages 502-5081.Simplify ( 3x)2.ANSWER9x2ANSWERa532b52. Simplify .a32b5第2页，共20页。3.The order of magnitude

2、 of Earths mass is about1027 grams. The order of magnitude of the sunsmass is about 1033 grams. About how many times as great is the suns mass as Earths mass?Lesson 8.3, For use with pages 502-508ANSWERabout 106第3页，共20页。Daily Homework QuizFor use after Lesson 8.2ANSWER641. Simplify . 63 6564ANSWER10

3、3ANSWERs2427r33. Simplify s83r3.1102. Simplify 107 4.第4页，共20页。Daily Homework Quiz For use after Lesson 8.2ANSWER103The order of magnitude of the power output of a nuclear-powered aircraft carrier is about 106 watts. The order of magnitude of peak power at Hoover Dam is about 109 watts. How many time

4、s as great is the power output of Hoover Dam as the power output of a nuclear-powered aircraft carrier?4.第5页，共20页。第6页，共20页。第7页，共20页。Use definition of zero and negative exponents EXAMPLE 1a. 3 2 Definition of negative exponents1 9 =Evaluate exponent.b. (7)0Definition of zero exponent132= 1第8页，共20页。Us

5、e definition of zero and negative exponents EXAMPLE 1= 25Simplify by multiplying numerator and denominator by 25.d. 0 5 a n is defined only for a nonzero number a.10 5(Undefined)=151 25 21c.Definition of negative exponents 1251=Evaluate exponent.第9页，共20页。GUIDED PRACTICEfor Example 1Evaluate the expr

6、ession. 0231.=11 64 =2. (8) 2123.3= 84. (1 )0= 1第10页，共20页。EXAMPLE 2Evaluate exponential expressionsa. 6 4 64Product of a power property= 60Add exponents.= 1Definition of zero exponent= 6 4 + 4第11页，共20页。EXAMPLE 2Evaluate exponential expressions1256=Evaluate power.c. 13 4Definition of negative exponen

7、tsEvaluate power.= 81 = 34Power of a power property= 4 4Multiply exponents.Definition of negative exponentsb. (4 2)214=4= 4 2 2第12页，共20页。EXAMPLE 2Evaluate exponential expressions1125=Evaluate power.d. 5 152Quotient of powers property= 5 3Subtract exponents.153=Definition of negative exponents= 5 1 2

8、第13页，共20页。GUIDED PRACTICEfor Example 25. 14 3= 64Evaluate the expression.6. (5 3) 1= 1257. ( 3)( 3 ) 55= 18. 6 26211296=第14页，共20页。EXAMPLE 3Use properties of exponentsSimplify the expression. Write your answer using only positive exponents.a. (2xy5)3= 23 x3 (y5)3= 8 x3 y15=y158x3Power of a product pr

9、opertyPower of a power propertyDefinition of negative exponents第15页，共20页。EXAMPLE 3Use properties of exponentsy5(2x)2(4x2y2)=(2x)2y54x2y2b.y5(4x)2(4x2y2)=y516x4y2=y316x4=Power of a product propertyDefinition of negative exponentsProduct of powers propertyQuotient of powers property第16页，共20页。EXAMPLE 4

10、Standardized Test PracticeThe order of magnitude of the mass of a polyphemus moth larva when it hatches is 10-3 gram. During the first 56 days of its life, the moth larva can eat about 105 times its own mass in food. About how many grams of food can the moth larva eat during its first 56 days?A1015

11、gramB0.00000001 gramC100 gramsD10,000,000 grams第17页，共20页。SOLUTIONEXAMPLE 4Standardized Test PracticeTo find the amount of food the moth larva can eat in the first 56 days of its life, multiply its original mass, 10 3, by 105.105 103The moth larva can eat about 100 grams of food in the first 56 days

12、of its life.ANSWERThe correct answer is C.ABCD= 102= 100= 105 + (3)第18页，共20页。GUIDED PRACTICEfor Examples 3 and 49x3y3xy 3 9. Simplify the expression . Write your answerusing only positive exponents.13x2y4ANSWER10. SCIENCE The order of magnitude of the mass of a proton is 104 times greater than the order of magnitude of