Logarithms – University of Plymouth









Logarithms

yet equivalent way of writing this expression is log2 16 = 4. This is stated as 'log to base 2 of 16 equals 4'. We see that the logarithm is the same as 
mc ty logarithms


Logarithms – University of Plymouth

16 janv. 2001 4. Logarithm of a Quotient. 5. Logarithm of a Power ... (b) We can do the same calculation using instead logs to base e.
PlymouthUniversity MathsandStats logarithms


6.2 Properties of Logarithms

4. ln(x) to base 10. Solution. 1. We apply the Change of Base formula with a = 3 and b = 10 to obtain 32 = 102 log(3). Typing the latter in the calculator 
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hp calculators - HP 35s Advanced uses of logarithmic functions Log

hp calculators. - 4 -. HP 35s Advanced uses of logarithmic functions - Version 1.0. Figure 5. Answer: The log to base 3 of 5 is 1.465 within the current 
Advanced Logarithms





The laws of logarithms

There are a number of rules known as the laws of logarithms. but the same base must be used throughout a calculation. ... c) log 4.
mc bus loglaws


Table of Contents - General Guide. - Turning on or off. Battery

Logarithms and Antilogarithms. Fraction calculation Regression Calculation. ‚ X² X³
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Logarithms.pdf

16 nov. 2017 Because we use a base 10 number system it seems straight forward that Logs with a base of 10 are used. The Log key on a scientific calculator ...
Logarithms


Logarithms:

Your calculator will be able to calculate logarithms to bases 10 and e (and possibly more). Usually the log button is used for base 10
logarithms





What is a logarithm? Log base 10

Now we have a new set of rules to add to the others: Table 4. Functions of log base 10 and base e. Exponents. Log base 10. Natural Logs sr.
logarithms


E – 1 General Guide .............................................. 3 Before Starting ...

10 juil. 2015 whether you want to reset the calculator and clear memory contents after selecting [ 3 ]. ... 4: ln X. Logarithmic Regression. Y = A + B lnX.
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213135 Logarithms – University of Plymouth Levelling-Up Basic MathematicsLogarithmsRobin HoranThe aim of this document is to provide a short, self assessment programme for students who wish to acquire a basic competence in the use of logarithms.Copyrightc

2000rhoran@plymouth.ac.ukLast Revision Date: January 16, 2001 Version 1.00

Table of Contents1.Logarithms2.Rules of Logarithms3.Logarithm of a Product4.Logarithm of a Quotient5.Logarithm of a Power6.Use of the Rules of Logarithms7.Quiz on Logarithms8.Change of BasesSolutions to QuizzesSolutions to Problems

Section 1: Logarithms 31. Logarithms (Introduction)LetaandNbe positive real numbers and letN=an:Thennis

called thelogarithm ofNto the basea. We write this asn= logaN:Examples 1(a)Since 16 = 24;then 4 = log216:(b)Since 81 = 34;then 4 = log381:(c)Since 3 =p9 = 912;then 1=2 = log93:(d)Since 31= 1=3;then1 = log3(1=3):

Section 1: Logarithms 4ExerciseUse the denition of logarithm given on the previous page to deter-

mine the value ofxin each of the following.1.x= log3272.x= log51253.x= log2(1=4)4.2 = logx(16)5.3 = log2x

Section 2: Rules of Logarithms 52. Rules of LogarithmsLeta;M;Nbe positive real numbers andkbe any number. Then the

following important rules apply to logarithms.1:logaMN= logaM+ logaN

2:logaMN= logaMlogaN

3:logamk=klogaM

4:logaa= 1

5:loga1 = 0

Section 3: Logarithm of a Product 63. Logarithm of a Product1. Proof thatlogaMN= logaM+ logaN:Examples 2(a)log64 + log69 = log6(49) = log636:

Ifx= log636;then 6x= 36 = 62:

Thus log

64 + log69 = 2:(b)log520 + log414= log52014:

Now 2014= 5 so log520 + log414= log55 = 1:Quiz.To which of the following numbers does the expression log

315 + log306 simplify?(a)4(b)3(c)2(d)1

Section 4: Logarithm of a Quotient 74. Logarithm of a Quotient1. Proof thatlogaMN= logaMlogaN:Examples 3(a)log240log25 = log2405= log28:

Ifx= log28 then 2x= 8 = 23;sox= 3:(b)If log35 = 1:465 then we can nd log306:

Since 3=5 = 06;then log306 = log335= log33log35:

Now log

33 = 1;so that log306 = 11465 =0465Quiz.To which of the following numbers does

the expression log

212log234simplify?(a)0(b)1(c)2(d)4

Section 5: Logarithm of a Power 85. Logarithm of a Power1. Proof thatlogamk=klogaMExamples 4(a)Find log10(1=10000):We have 10000 = 104;so 1=10000 =

1=104= 104:

Thus log

10(1=10000) = log10104=4log1010 =4;where

we have used rule 4 to write log

1010 = 1.(b)Find log366:We have 6 =p36 = 3612:

Thus log

366 = log36

3612

12log3636 =12:Quiz.If log35 = 1465;which of the following numbers is log3004?(a)-2.930(b)-1.465(c)-3.465(d)2.930

Section 6: Use of the Rules of Logarithms 96. Use of the Rules of LogarithmsIn this section we look at some applications of the rules of logarithms.Examples 5(a)log41 = 0:(b)log1010 = 1:(c)log10125 + log108 = log10(1258) = log101000

= log

10103= 3log1010 = 3:(d)2log105 + log104 = log1052+ log104 = log10(254)

= log

10100 = log10102= 2log1010 = 2:(e)3loga4+loga(1=4)4loga2 = loga43+loga(1=4)loga24

= log a4314loga24= loga42loga24 = log a16loga16 = 0:

Section 6: Use of the Rules of Logarithms 10ExerciseUse the rules of logarithms to simplify each of the following.1.3log32log34 + log3122.3log105 + 5log102log1043.2loga6(loga4 + 2loga3)4.5log36(2log34 + log318)5.3log4(p3)12log43 + 3log42log46

Section 7: Quiz on Logarithms 117. Quiz on LogarithmsIn each of the following, ndx:Begin Quiz1.logx1024 = 2(a)23(b)24(c)22(d)252.x= (logap27logap8logap125)=(loga6loga20)(a)1(b)3(c)3/2(d)-2/33.logc(10 +x)logcx= logc5)(a)2.5(b)4.5(c)5.5(d)7.5End Quiz

Section 8: Change of Bases 128. Change of BasesThere is one other rule for logarithms which is extremely useful in

practice. This relates logarithms in one base to logarithms in a dier- ent base. Most calculators will have, as standard, a facility for nding logarithms to the base 10 and also for logarithms to basee(natural logarithms). What happens if a logarithm to a dierent base, for

example 2, is required? The following is the rule that is needed.logac= logablogbc1. Proof of the above rule

Section 8: Change of Bases 13The most frequently used form of the rule is obtained by rearranging the rule on the previous page. We have log ac= logablogbcso logbc=logaclogab:Examples 6(a)Using a calculator we nd that log103 = 047712 and log

107 = 084510:Using the above rule,

Levelling-Up Basic MathematicsLogarithmsRobin HoranThe aim of this document is to provide a short, self assessment programme for students who wish to acquire a basic competence in the use of logarithms.Copyrightc

2000rhoran@plymouth.ac.ukLast Revision Date: January 16, 2001 Version 1.00

Table of Contents1.Logarithms2.Rules of Logarithms3.Logarithm of a Product4.Logarithm of a Quotient5.Logarithm of a Power6.Use of the Rules of Logarithms7.Quiz on Logarithms8.Change of BasesSolutions to QuizzesSolutions to Problems

Section 1: Logarithms 31. Logarithms (Introduction)LetaandNbe positive real numbers and letN=an:Thennis

called thelogarithm ofNto the basea. We write this asn= logaN:Examples 1(a)Since 16 = 24;then 4 = log216:(b)Since 81 = 34;then 4 = log381:(c)Since 3 =p9 = 912;then 1=2 = log93:(d)Since 31= 1=3;then1 = log3(1=3):

Section 1: Logarithms 4ExerciseUse the denition of logarithm given on the previous page to deter-

mine the value ofxin each of the following.1.x= log3272.x= log51253.x= log2(1=4)4.2 = logx(16)5.3 = log2x

Section 2: Rules of Logarithms 52. Rules of LogarithmsLeta;M;Nbe positive real numbers andkbe any number. Then the

following important rules apply to logarithms.1:logaMN= logaM+ logaN

2:logaMN= logaMlogaN

3:logamk=klogaM

4:logaa= 1

5:loga1 = 0

Section 3: Logarithm of a Product 63. Logarithm of a Product1. Proof thatlogaMN= logaM+ logaN:Examples 2(a)log64 + log69 = log6(49) = log636:

Ifx= log636;then 6x= 36 = 62:

Thus log

64 + log69 = 2:(b)log520 + log414= log52014:

Now 2014= 5 so log520 + log414= log55 = 1:Quiz.To which of the following numbers does the expression log

315 + log306 simplify?(a)4(b)3(c)2(d)1

Section 4: Logarithm of a Quotient 74. Logarithm of a Quotient1. Proof thatlogaMN= logaMlogaN:Examples 3(a)log240log25 = log2405= log28:

Ifx= log28 then 2x= 8 = 23;sox= 3:(b)If log35 = 1:465 then we can nd log306:

Since 3=5 = 06;then log306 = log335= log33log35:

Now log

33 = 1;so that log306 = 11465 =0465Quiz.To which of the following numbers does

the expression log

212log234simplify?(a)0(b)1(c)2(d)4

Section 5: Logarithm of a Power 85. Logarithm of a Power1. Proof thatlogamk=klogaMExamples 4(a)Find log10(1=10000):We have 10000 = 104;so 1=10000 =

1=104= 104:

Thus log

10(1=10000) = log10104=4log1010 =4;where

we have used rule 4 to write log

1010 = 1.(b)Find log366:We have 6 =p36 = 3612:

Thus log

366 = log36

3612

12log3636 =12:Quiz.If log35 = 1465;which of the following numbers is log3004?(a)-2.930(b)-1.465(c)-3.465(d)2.930

Section 6: Use of the Rules of Logarithms 96. Use of the Rules of LogarithmsIn this section we look at some applications of the rules of logarithms.Examples 5(a)log41 = 0:(b)log1010 = 1:(c)log10125 + log108 = log10(1258) = log101000

= log

10103= 3log1010 = 3:(d)2log105 + log104 = log1052+ log104 = log10(254)

= log

10100 = log10102= 2log1010 = 2:(e)3loga4+loga(1=4)4loga2 = loga43+loga(1=4)loga24

= log a4314loga24= loga42loga24 = log a16loga16 = 0:

Section 6: Use of the Rules of Logarithms 10ExerciseUse the rules of logarithms to simplify each of the following.1.3log32log34 + log3122.3log105 + 5log102log1043.2loga6(loga4 + 2loga3)4.5log36(2log34 + log318)5.3log4(p3)12log43 + 3log42log46

Section 7: Quiz on Logarithms 117. Quiz on LogarithmsIn each of the following, ndx:Begin Quiz1.logx1024 = 2(a)23(b)24(c)22(d)252.x= (logap27logap8logap125)=(loga6loga20)(a)1(b)3(c)3/2(d)-2/33.logc(10 +x)logcx= logc5)(a)2.5(b)4.5(c)5.5(d)7.5End Quiz

Section 8: Change of Bases 128. Change of BasesThere is one other rule for logarithms which is extremely useful in

practice. This relates logarithms in one base to logarithms in a dier- ent base. Most calculators will have, as standard, a facility for nding logarithms to the base 10 and also for logarithms to basee(natural logarithms). What happens if a logarithm to a dierent base, for

example 2, is required? The following is the rule that is needed.logac= logablogbc1. Proof of the above rule

Section 8: Change of Bases 13The most frequently used form of the rule is obtained by rearranging the rule on the previous page. We have log ac= logablogbcso logbc=logaclogab:Examples 6(a)Using a calculator we nd that log103 = 047712 and log

107 = 084510:Using the above rule,


  1. log calculator base 4