1. Simplifying Logarithms
Honors Precalculus
October 23, 2017
Mr. Agnew

2. Essential Question Essential Vocabulary
What is a logarithm and how do you evaluate logarithms?
Essential Vocabulary
Exponential Functions
Logarithmic Functions
Common and Natural Logarithms
Change of Base Formula

3. Definition of Logarithm
Inverse of exponential function
“Logarithm is an exponent”
Definition…

4. Inverse of Exponentials
How do you find the inverse of a function?
On the class starter today, we looked at the graphs of inverses of exponential functions.
The inverse of exponential functions are logarithmic functions.
Graphs Examples…

5. Simplifying Logarithms
To simplify a logarithm, use definition to rewrite as exponential equation.
Set logarithm equal to x, convert equation, and find x.
Guided Practice Examples

6. Special Logarithms Common Logarithm Natural Logarithm
Logarithm with base of 10 (i.e., log 3)
Natural Logarithm
Logarithm with base of e (i.e., ln 3)
Both can be evaluated on calculator.

7. Domain of Logarithms
The logarithm of a negative number (or 0) does not exist.
To find domain, set “big number” greater than zero.
Examples…

8. Change of Base Formula
Guided Practice: Page 308 #72 – 78 (Even)

9. Homework Page 298 Page 309 # 73 – 77 (Odd)
#29 – 36, 41, 44, 46, 57, 58, 77, 81, 85, 91, 97, 103, 104
Page 309
# 73 – 77 (Odd)