Lesson #41
Logarithms




Quote of the Day:
"Tell me and I'll forget. Show me and I may not remember. Involve me, and I'll understand." -- Native American saying

Objectives:
The student will discover the basic properties of logarithms.

The student will apply the laws of logarithms to problems.

The student will solve logarithmic equations.



1. Bell Ringer.

2. Top Ten Teacher Log Expressions

3. Define a logarithmic as an exponent:


4. Group Activity with logs

After giving students the definition of a logarithm, divide the class into pairs or groups of three.

Each group is given two envelopes containing several index cards (Four sets of sample cards appear below).

Each group is given about three minutes to make correct mathematical statements using the cards in the envelopes.

Not all cards in the envelope are used in the equation.

At a signal, a spokesperson for each group reads the equations and I write them on the chalkboard, grouping similar equations together.

The students then try to formulate a general statement that summarizes the pattern found in the groups of similar questions.

We write these conjectures above each group:



Here is a set of sample cards:



5. Have students write down everything that they know about logarithms and put this on the board.   This list should include the following:

(a) LOGARITHM = EXPONENT
(b) the three properties of a log
(c) the change of base theorem (below)
(d) perhaps, graphs???

6. Examples:



7. Change of Base Theorem



8. What do you call African Drum Music?
Answer: Logarithm



9. Assignment:
p. 74 (1, 4a, 5, 7, 13)
Log Worksheet

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Send any comments or questions to: David Pleacher