1. 3.2: Logarithmic Function and
Pre-Calculus Honors
3.2: Logarithmic Function and
Their Graphs
Quiz : Friday
HW: p (46-50 even, 64, 66, 70, 74, even)
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2. Logarithmic Function

3. Rewrite from a log to an exponential or exponential to log.

4. The Natural Logarithmic Function
The function f (x) = ex is one-to-one and so has an inverse function. This inverse function is called the natural logarithmic function.

5. Logarithmic Function
The logarithmic function with base 10 is called the common logarithmic function.
Properties are also true for natural log.

6. Solve for x.

7. Simplify the expression.

8. Example 9 – Finding the Domains of Logarithmic Functions
Find the domain of each function.
a. f (x) = ln( x – 2) b. g (x) = ln(2 – x) c. h (x) = ln x2

9. 3.2: Graph of Exponential and Logarithmic Function
In the same coordinate plane f (x) = 2x and g (x) = log2x are sketched below.
f(x) and g(x)
are inverses of
each other, so
their graphs
are a reflection
over y = x.

10. Find the domain, asymptote, x-int. Graph.

11. Find the domain, asymptote, x-int. Graph.

12. Find the domain, asymptote, x-int. Graph.

13. Example 10 – Psychology
Students participating in a psychology experiment attended several lectures on a subject and were given an exam. Every month for a year after the exam, the students were retested to see how much of the material they remembered. The average scores for the group are given by the human memory model, f (t) = 75 – 6 ln(t + 1), 0  t  12, where t is the time in months.
What was the average score
on the original exam (t = 0)
at the end of t = 2 months?

14. Analyzing Graphs of Functions
Use a graphing utility to graph the function. Find the domain and determine when the function is increasing/decreasing. Find any relative maximum and minimum values of the function. Round to three decimal places.