## Lesson 31: Logarithms

** Description:**The lesson begins with an application problem to motivate the necessity and use of a logarithm. The formal definition linking logs and exponents is then introduced. Exercises in writing exponential equations as logarithms follows before a calculator based method for approximating logarithmic values is discussed. The common log, i.e. logs of base 10, is introduced and a procedure for solving common log equations with a calculator is presented, along with various caveats about proper syntax for the calculator. The lesson concludes with exponential modeling problems where logs may be employed to find the desired exponent.

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**Subject(s):**- Mathematics
- Mathematics > Algebra

**Educational Level(s):**- College & Beyond

**Instructional Component Type(s):**- Curriculum: Lesson Plan

- From: San Diego Area Knowledge Exchange for Developmental Math (SAKE)
- Contributed By: SAKE Owner SAKE Owner

The lesson begins with an application problem to motivate the necessity and use of a logarithm. The formal definition linking logs and exponents is then introduced. Exercises in writing exponential equations as logarithms follows before a calculator based method for approximating logarithmic values is discussed. The common log, i.e. logs of base 10, is introduced and a procedure for solving common log equations with a calculator is presented, along with various caveats about proper syntax for the calculator. The lesson concludes with exponential modeling problems where logs may be employed to find the desired exponent.