# Logarithms and exponential models

• Mar 8th 2009, 05:57 PM
Gitano
Logarithms and exponential models
Hello, I am currently a bit confused regarding two problems.

1. Q= 40e^ (t-5)/12

2. Q= 2e^ (1-3t/4)

Directions tell me to find the values of a, r, and k. For some reason I am finding these two particular problems somewhat tricky.

Any help and feedback would be appreciated, thanks.
• Mar 9th 2009, 12:35 AM
earboth
Quote:

Originally Posted by Gitano
Hello, I am currently a bit confused regarding two problems.

1. Q= 40e^ (t-5)/12

2. Q= 2e^ (1-3t/4)

Directions tell me to find the values of a, r, and k. For some reason I am finding these two particular problems somewhat tricky.

Any help and feedback would be appreciated, thanks.

The wording of your question is kind of cryptic. So I'm guessing:

The general equation of exponential growth is:

$\underbrace{a}_{amount} = \underbrace{k}_{start\ value} \cdot ~ e^{\underbrace{r}_{rate}}$

to #1:

a = Q, k = 40, $r = \dfrac{t-5}{12}$

I'll leave the rest for you.
• Mar 9th 2009, 05:53 PM
Gitano
Thanks for the feedback.

Seems a lot simpler than i thought.