Section 7 3 Logarithms and Logarithmic Functions Objectives

Section 7 -3 Logarithms and Logarithmic Functions Objectives: 1. Evaluate logarithmic expressions. 2. Graph logarithmic functions.

Use this statement to change this from log form to exponential form Rewrite the log statement (switch the two sides of the equals sign) Find the values of b, x, and y b=2 x=8 y=3 8=2 3 Write in exponential form

Rewrite the log statement (switch the two sides of the equals sign) to be in form Find the values of b, x, and y b=4 Write in exponential form 1 x = 256 y = -4 1 = 4 -4 256

Use this statement to change this from exponential form to log form exponential form b = 15 x = 3375 y=3 3 = log 15 3375 Rewrite the log statement (switch the two sides of the equals sign) to be in form Find the values of b, x, and y Write in log form

Use this statement to change this from exponential form to log form exponential form b=4 Rewrite the log statement (switch the two sides of the equals sign) to be in form x=2 1 y= 2 1 = log 2 4 2 Find the values of b, x, and y Write in log form

This will work on every calculator, but many graphing calculators have an option of log. BASE( To see if you calculator has this option: Press MATH Scroll down to A

Method 1: Use the change of base formula to rewrite this expression Type this in a calculator and get the answer as a fraction Method 2: Use the log. BASE option

OR Use the change of base formula (or log. BASE) to graph the function Use the table to get values to graph *The graph looks like it ends, but if you zoom in it goes on forever, but does NOT cross the y-axis! Don’t forget to draw arrows at both ends of the graph!

Vertical Stretch by 3 Up 1

Vertical Shrink by 1/2 Right 3