Logarithmic Functions & Their Graphs Sec. 5.2 Logarithmic Functions & Their Graphs

Logarithmic Function is the inverse of exponential function Definition of Logarithmic Function y = logax if and only if x = ay f(x) = logax for x>0 & a>0, a≠1 Natural log is represented by ln y = ln x means logex if x = ey

logax Means what exponent must a be raised to to get x. log28 Means what must 2 be raised to in order to get 8. log28 = 3

log93 Set it up in exponential form 9x = 3 Try these log66 log5(1/25)

Common Logarithmic Function Has 10 as its base Denoted with just log What the log on the calculator represents

What would these be? log 10 2 log 2.5 log (-2)

Properties of Logarithms logaa=1 logaax=x If logax = logay then x=y

also ln 1 = 0 ln e = 1 ln ex = x If ln x = ln y then x=y