1Math 442 Intro to PDE

Homework


Due
Section Pages Exercises Comment
HW 1 Aug 31
1.1
2abc, 3bcef, 10, 12


1.2
1, 3, 6, 7
HW 2 Sep 7
1.3 p18-19 2, 4, 6 #2: take a naive approach; ditermine T and re-use the wave equation
#4: "homogeneity in the horizontal directions" means that u=u(z,t) is independent of x and y
#6: we are assuming that kappa , c and rho are all constant and we write k=kappa/(c rho):
also, you can use formula (5) on p151


1.4 p24-25 1, 3, 5 #3: note that D is a region in 3 dimensions
HW 3 Sep 14
2.1 p36-37
1, 3, 5, 8, 9


2.2 p40
1, 2, 3, 5
HW 4 Sep 21
2.3 p44-45
3, 5(a), 6 In 3(a), show u(x,t) >= 0 instead of u(x,t) > 0.


1.5 p27
2


2.4 p50-51
1, 4
HW 5 Sep 28 2.4, 2.5
Download the homework Answer Key: p1, p2, p3, p4
No HW Oct 5 3.3, 3.4

You may solve #2 in the section 3.4. (Don't turn this in.)
HW 6 Oct 12
4.1 p87
2, 4 In 2, Strauss means Dirichlet BCs.
In 4, explain where the assumption 0 < r < 2 pi c/l is used.


4.2 p90
2, 3 In 2(a), it is better to wirte the eigenfunctions as cos (n pi x/2l) for odd n.
In 3, make sure you consider all cases: lambda > 0, = 0, < 0.


4.3 p97
1 Consider only when a < -1/l.
HW 7 Oct 19
5.1 p108
8


5.2 p113
9, 11, 17


5.3 p118-119
3, 6 In 3, change the BCs, using instead that u_x(0,t)=0 and u(l,t)=0. Use the given ICs. You may want to use the result from Exercise 4.2.2 in your previous homework.
HW 8 Oct 26
5.3 p120
15


5.4 p129-131
5, 8(a)(b), 9, 13, 18 In 13, use l=pi.
HW 9 Nov 2
5.4 p131
13 Use l=pi. Even if you aleady handed in this problem for HW 8, turn this in again.


5.5 p139-140
5, 12 In 5, put the absolute value signs outside of the series on left first,and then show it.
In 12, you may use #5.4.9.


5.6 p144-145
5, 8, 9, 13(a)(b) In 5, you are NOT allowed to use the formula (12) immediately. Assume c=1.
In 5, also, note that sin 5x and sin3x are already in the form of Fourier sine series on (0, pi).
In 9, assume h=1 and k=3.
In 13, you can refer #4.1.4. But here, r is just positive.
No HW Nov 9



HW 10 Nov 16
6.1 p154
2, 5, 9


6.2 p158-159
3, 6, 7(a) In 6, assume g(x,y)= cos(2 pi x) - 2cos(3 pi x)cos(4 pi y).
In 7, use exponential functions instead of cosh and sinh.
HW 11 Nov 30 6.1, 6.3, 2.4, 9.4
Download the homework
HW12 Dec 7


OPTIONAL
If you hand this HW in, I will drop two lowest HWs including the result of this.
No late HW will be accepted (4:50 pm).
Don't drop in my mailbox. Bring yours to the class or to my office.
Even you don't hand this HW in, I strongly recommend you solve these problems before the final exam.


10.3 p263-264
6, 8, 10 In 6, use (11) on p270 or hint in #6.1.2.
In 8(a), see #4.3.1.
In 10, see Example 2 on p262.


10.6 p278
6 See Example 2 and the table on p262.


12.3 p329-330
1(5)(6)(7), 2(iii)-(vi), 9


12.4 p333
1



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