**Module 2.4 Exercises: 4abcde** on p. 65. For part **e**, I just googled on **integration tool** and found **http://integrals.wolfram.com**. You'll have to use ** x** instead of

**Module 3.2 Exercise: 4cde** on p. 84. This is a bit tricky because the initial value involves a subtraction (object's temperature T minus room temperature 25). Usually you'd have *dT/dt = kT* with solution *T = T*_{0}*e** ^{kt}*. But here the change is proportional not to

**Module 3.3 Exercise: 5** on p. 93. 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).