# Common and Natural Logarithms Contributed by: OBJECTIVES:
1. Evaluate common logarithms using a calculator.
2. Use common logarithms in applications.
3. Evaluate natural logarithms using a calculator.
4. Use natural logarithms in applications.
Sec 11.5 - 1
2. Chapter 11
Inverse, Exponential
and
Logarithmic Functions
Sec 11.5 - 2
3. 11.5
Common and Natural
Logarithms
Sec 11.5 - 3
4. 11.5 Common and Natural Logarithms
Objectives
1. Evaluate common logarithms using a
calculator.
2. Use common logarithms in applications.
3. Evaluate natural logarithms using a
calculator.
4. Use natural logarithms in applications.
5. 11.5 Common and Natural Logarithms
Common Logarithms
6. 11.5 Common and Natural Logarithms
Common Logarithms
7. 11.5 Common and Natural Logarithms
Evaluating Common Logarithms
8. 11.5 Common and Natural Logarithms
Common Logarithms in Applications
The loudness of sound in decibels is given by the formula
 I 
y 10log  
 I0 
Where I0 is the weakest sound detected by the observer and I is
the intensity of the given sound.
That is, find the value of I0 is 51,000 times I.
9. 11.5 Common and Natural Logarithms
Common Logarithms in Applications
 I 
y 10log  
 I0 
 51,000 
y 10log  
 I0 