
Base
a is the base of the exponential expression a^{x}. a is also the base of the logarithmic expression log_{a}x.

Common Logarithmic Function
The logarithmic function f (x) = log_{1}0x.

Exponent
x is the exponent in the exponential expression a^{x}. It means a is multiplied by itself x times.

Exponential Function
A function of the form f (x) = a^{x}, where a > 0, a≠1, and x is any real number

Halflife
The time it takes for a exponentially decaying substance to lose half its mass.

Logarithm
An expression of the form log_{a}x. If log_{a}x = b, a^{b} = x.

Logarithmic Function
A function of the form y = log_{a}x where x = a^{y}, a > 0, and a≠1. This example is a logarithmic function with base a.

Natural Exponential Function
The function f (x) = e^{x}.

Natural Logarithmic Function
The logarithmic function f (x) = log_{e}x = ln x.
Terms
Formulae
Change of Base  log_{a}x = , where a, b, and x are all positive real numbers and a, b≠1. 