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TEST RESULTS. Very Scary We are trying to figure out what to do with the results… I will keep you posted…. Definitions. log a b a is called the base b is called the argument. Definitions. ln ln = log e e is Euler’s constant e=2.718. Definitions (p.159). If: log c p = q
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TEST RESULTS • Very Scary • We are trying to figure out what to do with the results… I will keep you posted…
Definitions logab a is called the base b is called the argument
Definitions ln ln = loge e is Euler’s constant e=2.718
Definitions (p.159) If: logcp = q Then we have the following equivalence: cq = p LogarithmicForm ExponentialForm
Definitions (p.159) ***NOTE log10x = logx When the base is 10, we just write logx
Example 1 log28 = 3 True, since: 23 = 8
How to use your calculator! logcx = logx or lnx logc lnc You can use either the log or the ln button on the calculator!
Example 2 Calculate log216 log216 = (log16)/(log2) = 4 (on calculator) Or mentally: 2x = 16 So x = 4
Example 3 Determine x when log3x = 4 Exponential Form: 34 = x 81 = x
Properties of Logs Section 4.5
#1 – loga1 = 0 No matter what the base is,if the argument is 1, then it equals 0 Examples log21 = 0 log51 = 0 log96501 = 0
#2 – logaa = 1 If the base and the argument are the same,then it equals 1 Examples log22 = 1 log55 = 1 log9696 = 1
#3 – logaan = n If the base and the argument are the same,and the argument has an exponent,then it equals the exponent Examples log227 = 7 log558 = 8 lne2 = logee2 = 2
#4 – alogaM = M Examples 2log27 = 7 7log79 = 9 986log98676 = 76
Use the property alogaM = M to express 6 as a power of 9 alogaM = M M=6 so… aloga6 = 6 a=9 so… 9log96 = 6
Homework Workbook p. 159 #1,2 p. 160 #3, 7 p. 174 #1,2, 3 Want extra practice? p.159 Activity #2 p.160 #4