Math 3200 Sample Final Exam
Briggs' Section - Spring 1998
This sample exam is probably longer than a typical two-hour in
class exam.
- Find the general solution of the following three ODEs.
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-
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The cost of living in a particular country has been rising at 5.5% per
year for many years. Assuming this growth rate continues, what is the
doubling time for the cost of living?
- The owners of a fish hatchery harvest and resupply fish in such a
way that the fish population obeys the ODE
- Find the general solution of this ODE.
- Find the solution that satisfies the initial condition
y(0)=500.
- Does the fish population increase or decrease in time? If it
increases, find when the fish population reaches 10,000. If it
decreases, find when the fish population reaches zero.
- Which of the following sets of functions are fundamental sets for
the ODE y''(t)-16y(t)=0? Explain your reasoning for each case.
- Find the general solution of the following ODEs.
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- An undamped oscillator is governed by the following initial value
problem.
Use Laplace transforms to find the solution of this initial value
problem. Make a rough sketch of the solution over three full periods of
the solution.
- Consider the ODE xy''(x)-2y(x)=0. Find a recurrence relation for
the coefficients of a power series solution about the point x=0.
Answers. C is an arbitrary constant.
1a.
1b.
.
1c.
.
2.
3a.
.
3b.
.
3c. y(t)=0 when
.
4. Only the third set is a fundamental set.
5a.
.
5b.
6.
.
7.
.
Bill Briggs
Fri May 1 20:16:19 MDT 1998