Logarithm Practice WECHS 13 December 2010 Logarithm Example

Logarithm Practice WECHS – 13 December 2010

Logarithm Example 1 � Given that log 2. 72 = 0. 4346, approximate the following without a calculator: log 0. 272, log 272, and log 0. 00272. � How would you solve this?

Logarithm Example 1 � Given that log 2. 72 = 0. 4346, approximate the following without a calculator: log 0. 272, log 272, and log 0. 00272. � Use the Product Property:

Logarithm Example 2 � Solve the equation 4=3 x using logs in base 3 and base 10. � How do logs allow you to solve for x?

Logarithm Example 2 � Solve the equation 4=3 x using logs in base 3 and base 10. � How do logs allow you to solve for x? � Because the Product Property lets you take an exponent out of the log. PRODUCT PROPERTY

Logarithm Example 2 � Solve the equation 4=3 x using logs in base 10 and base 3. ◦ First take the log of both sides: ◦ So,

Logarithm Example 2 � Solve the equation 4=3 x using logs in base 10 and base 3. ◦ First take the log of both sides: ◦ So, ◦ Finally,

Logarithm Example 2 � Our solution works no matter what base you use for the logarithm. What if we change to base 3?

Logarithm Example 2 � Our solution works no matter what base you use for the logarithm. What if we change to base 3? ◦ So,

Practice Problems � EOC practice problems 1 -4 at: http: //www. ncpublicschools. org/docs/accountability /testing/eoc/sampleitems/alg 2/20071207 alg 2 g 1. pdf Problem 1: pure calculator Problem 2: change from log to exponent Problems 3 & 4: harder problems – use logs to solve equations with x in the exponent.