Posted by **mysterychicken** on Thursday, June 20, 2013 at 11:45am.

1. Exponential growth follows the formula y=a(1+r)^x and exponential decay follows the formula y=a(1-r)^x..

This seems obviously TRUE

But now I'm having doubts about the decay formula

Is this true or false?

- Math -
**Steve**, Thursday, June 20, 2013 at 11:58am
Normally exponential growth is expressed as

f(t) = a e^kt

and exponential decay is

f(t) = a e^-kt

If 0<r<1, then the statement is true, since then we have

1-r < 1 so we have a fraction, and exponential of a fraction is e^-kt for some k.

With no restrictions on r, things get a bit dicier.

I think in your case, say you have a 12% growth rate. Then

f(x) = a(1.12)^x

At 12% decay rate would then mean that 88% is left after each interval, so you would indeed have

f(x) = a(1-.12)^x = a(.88)^x

## Answer This Question

## Related Questions

- math - 18. Exponential growth follows the formula y= a(1+r)^x and exponential ...
- Math Please Help - How are exponential growth and decay present in the real ...
- Math - Part 1: How are exponential growth and decay present in the real world? ...
- Algebra - Determine if the equation y = 2^x represents exponential growth or ...
- Emergancy help!!!!!!!!! - Classify the model as exponential growth or ...
- Math - Classify the model as exponential growth or exponential decay. Identify ...
- Chemistry (Check) - True or False The empirical formula of a compound is always ...
- Math - Part 1: How are exponential growth and decay present in the real world? ...
- math - Part 1: How are exponential growth and decay present in the real world? ...
- math - another ? - exponentials - The two formulas f(t) = Pa^t and f(t) = Pe^rt ...

More Related Questions