Introduction to logarithms

5 videos
3 skills
Learn how we define logarithms and use this definition in order to evaluate various logarithms. For example, evaluate log_2(8) as 3 by realizing that 2^3=8.

Introduction to logarithms

VIDEO 7:02 minutes
Sal explains what logarithms are and gives a few examples of finding logarithms.

Evaluate logarithms (basic)

PRACTICE PROBLEMS
Evaluate basic logarithmic expressions by using the fact that a^x=b is equivalent to log_a(b)=x.

How to evaluate advanced logarithmic expressions (example)

VIDEO 4:20 minutes
Sal evaluates log_2(8), log_8(2), log_2(1/8), and log_8(1/2).

Evaluate logarithms (advanced)

PRACTICE PROBLEMS
Evaluate advanced logarithmic expressions by using the fact that a^x=b is equivalent to log_a(b)=x.

How to rewrite exponential equations in logarithmic form and vice versa (example)

VIDEO 1:42 minutes
Sal rewrites 100=10^2 as a logarithmic equation and log_5(1/125)=-3 as an exponential equation.

How to plot points of a logarithmic function that correspond to the inverse exponential function (example)

VIDEO 4:10 minutes
Given a few points on the graph of an exponential function, Sal plots the corresponding points on the graph of the corresponding logarithmic function.

How to find missing values in tables of inverse exponential and logarithmic functions (example)

VIDEO 5:59 minutes
Given incomplete tables of values of b^x and its corresponding inverse function, log_b(y), Sal uses the inverse relationship of the functions to fill in the missing values.

The inverse relationship of exponents and logarithms

PRACTICE PROBLEMS
Solve various problems that focus on the relationship between a^x=b and log_a(b)=x.