# Continuous growth and decay

### Continuous growth and decay

###### Basic concepts:

- Natural log: ln
- Solving exponential equations with logarithms

###### Basic concepts:

- Natural log: ln
- Solving exponential equations with logarithms

${A_f}$: final amount

${A_i}$ : initial amount

${e }$ : constant = 2.718…

${r }$ : rate of growth/decay

• growth rate of 7% $\to {r = {7\over100} = 0.07}$

• growth rate of 15%$\to {r = - {15\over100} = - 0.15}$

${t }$ : total time given