The exam will be on Tuesday, October 26, 1999, from 9:30 am to 10:45 am. It will cover Homework Problems 23 through 47. It consists of five problems, each worth 16 points. More precise information on the various problems follows.

1. Determine an integrating factor for a given equation and find a solution of this equation. To do this, you surely have to know all of Problems 23-28.

2. Find a difference equation according to a described situation (see Problems 30 and 33) and solve it. It will be a linear first order difference equation with constant coefficients, but the b from the lecture won't be zero.

3. Solve an initial value problem involving a linear second order differential equation with constant coefficients, where both roots of the characteristic polynomial are real and distinct. See Problems 34, 35, and 36.

4. Calculate the Wronskian of two solutions of a second order differential equation. Make sure you can do all of Problems 38-46.

5. Solve an initial value problem involving a linear second order difference equation with constant coefficients, where both roots of the characteristic polynomial are real and distinct. See Problem 47.