# Problem Set #2

All three exercises are from Module 2.3 on p. 40.
**Exercise 3** (I apologize for the use of Imperial units.)
**Exercise 4** In the past I've skipped this problem because of the amount of math invovled, but considering how
many of you are interested in medicine, I wanted us to take a stab at it this time.
As usual, when you see “solve using calculus”, you have two choices:
- Do like I do, and google it. I found a several solutions
by googling GOMPERTZ EQUATION, which requires you to translate the between textbook's variables
(
*N*, *M*, *k*) and the ones in the solution (*y*, *K*, *r*),
something you often have to do it situations like this. Even then, it's nontrivial, so here is
one weird trick you can use.
- Be a calculus hero and solve it with your skillz, for
teh extra creditz.

**Exercise 5** I would use Excel to produce the graph (part **a**): Enter the numbers 0 through 10 in Column A, then in cell B1 type the formula **= EXP(-A1)**, and copy-and-paste into the remaining cells in column B. Then do **Insert/Scatter** and choose the smooth-line plot. Then copy-and-paste the plot into your writeup. For **5b-f**, Excel and Vensim can also help you to match the formulas (A-F) with the English descriptions (b-f),but all you need to turn in for these is the final answer (what goes with what).