Homework

MATH 451-500, spring 2005

This is a list of the lectures we had so far, with the homework set.

All section numbers are from Boyce and DiPrima, unless stated otherwise. The exercises marked by a star (*) are what I would call "interesting" (usually, but not always, more difficult than the average).

N Date Homework exercises
1 Jan 18 Read Chapter 1, Section 2.1
(p.24) 8, 11*;  (p.10) 27, 31;  (p.39) 7-12, 16-20, 38*
2 Jan 20 Read Sections 2.2, 2.6
(p.47) 2, 4, 6, 8, 10, 12, 14, 16;   (p.99) 2, 4, 6, 8, 14, 17, 18
3 Jan 25 2.6: 23
Braun 1.3 1, 2, 7
4 Jan 27 read Braun 1.10, prove |a+b|<=|a|+|b|
and same for integrals
5 Feb 1 read Braun 1.10, prove properties of Lipschitz functions
and uniqueness for DEs with Lipschitz right-hand side
6 Feb 8 Braun 1.10: 5, 6, 7, 12, 16, 19
Ex.16c has a misprint. Should be 1/(2a), not (1/2)a.
7 Feb 10 Braun 2.1: 9, 10*, 13, 16, 17
8 Feb 15 no homework -- prepare for the exam
9 Feb 17 -- exam 1 --
10 Feb 22 BDi, p.190: 7, 9, 11, 12, 13, 15, 28-31
11 Feb 24 BDi, p.184: 7-18
12 Mar 1 BDi, p.204: 15, 19, 20, 26
BDi, p.214 6, 12, 13, 17
13 Mar 3 bonus problem: for what value(s) of b will the solution of
{x''+bx'+9x=0, x(0)=90, x'(0)=-810} remain positive for all t?
14 Mar 8 7.2 all
15 Mar 10 7.3 6-24
16 Mar 22 7.4 6, 7, 8; 7.5 1,3,5,6,12
17 Mar 24 7.5 24-27
18 Mar 29 7.6 1-6, 13-20
19 Mar 31 exam 2
20 Apr 5 7.7 3, 5, 7, 13, 15
21 Apr 7 7.8 2, 5, 6; 7.9 1, 5, 14, 15, 16
22 Apr 12 9.1 1-12abc, 17, 20, 21
23 Apr 14 9.2 1-4, 5-10a (here is a nice plot of trajectories from question 19)
24 Apr 19 9.3 5-15abc, 17, 24, 25, 26
23 Apr 21 -- quiz 3 -- (here is a sketch of the phase plane)

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