# What is the exponential decay formula?

Jul 9, 2014

There are different ways of representing the Half-Life (exponential decay):

1) $A = {A}_{0} \cdot {2}^{- \frac{t}{T} _ \left(\frac{1}{2}\right)}$

$A$: Final amount
${A}_{0}$: Initial amount
$- t$: time
${T}_{\frac{1}{2}}$: the half-life

2) $A = {A}_{0} \cdot {e}^{- k t}$

$A$: Final amount
${A}_{0}$: Initial amount
$- k$: decay constant
$t$: time

Figure out what you're given and what you need to find from reading a question carefully and plug-in to solve!