• because logarithms are the inverse of exponents, logarithmic functions are the inverse of exponential functions

Comparing Exponential and Logarithmic Functions, y = 10^x and y = log[10]x

• the inverse of y = c^x is y = log[c]x
• x and y are flipped
• in y = c^x, "x" represents the exponent "c" is raised to, and "y" is the result of "c^x"
• in y = log[c]x, "y" represents the exponent "c" is raised to, and "x" is the result of "c^y"

Comparing Exponential and Logarithmic Functions, y = 2^x and y = log[2]x

Domain of a Logarithmic Function

• the argument of a logarithm must be greater than 0
• log(x), x > 0
• log(x + 1), x + 1 > 0, x > -1
• log(2x - 3), 2x - 3 > 0, x > 3/2

Graphing Logarithmic Functions Using a Graphing Calculator

• a graphing calculator's log button only uses base 10
• change the base of the logarithm to base 10 to input