A common logarithm is a logarithm with base 10, often denoted as $\log_{10}$ or simply log. It is used to solve equations involving exponential growth or decay where the base of the exponent is 10.
Natural Logarithm: A logarithm with base e (approximately 2.718), denoted as $\ln$. It is widely used in calculus and natural phenomena.
Exponential Function: $f(x) = a^x$, where a is a positive constant. Exponential functions describe rapid growth or decay.
$e$ (Euler's Number): $e$ is an irrational constant approximately equal to 2.71828, serving as the base for natural logarithms.