MATH 550

Professor Girardi

Chapter 7 Homework



Section

pages

I.S.

Recall the handout with hints to assorted problems from Chapter 7. Surely you will use these solutions wisely: giving a problem a good honest shot before looking at the solution. I expect you to review a solution before asking a question in class.
7.0   7.a Read the following about paths & curves: 2.6 and 7.a from the Informal Summary, from the bottom of page 406 through ex 7 on page 408, from the middle of page 412 through the middle of page 413.
Read the 3 page handout with comments on 1997 Quiz 6, which is the first few pages of the handout containing hints on Ch 7 homework.
7.1 400 7.b 3, 4, 7a, 9, 10, 12, 13
7.2 402 7.c read examples 1-9, 11, 12 from this section
7.2 417 7.c 1, 3, 4, 10, 11, 12, 14, 17
7.2 420 7.c Problem 18 is unrealistic. So instead of doing this problem, figure out why it is unrealistic. Hint: look at the speed of the biker. For help, look at the Maple worksheet ch7s2n18.mws.
7.3 427 7.d 3, 4, 5, 6(ellipsoid), 7, 10b, 12 (a-7.d.2, b-2.11part 1, c-2.11part2). Hint: helpful on some is 7.f.2.
7.4 438 7.e 1, 2, 4(just using formula (3)), 6, 9, 20 (coupler = sphere minus what is bored out). Hint: helpful on some is 7.f.2.
Remarks
  • Open surface means without lids.
  • Closed surface means with lids.
  • In the solutions, some of the problems are done two ways: the second way using either Green's, Stokes', or Gauss' Theorems, which we will cover in Chapter 8.
7.5 466 7.e 1 (it's a 4 sided surface with vertices (1,0,0), (1,1,0), (0,0,1),(0,0,0)),
3(easier way than in SG is to use 7.d.5 and do two ways using 2 different parameterizations of the hemisphere),
4(ans: 0), 5, 7, 8,
9(without loss of generality, (x_0,y_0,z_0) can be any point on the sphere (why?) so pick a point that makes integration do-able),
10, 11, 19.
Hint: Helpful on several is 7.f.2
7.6 460 7.f&g 4(enclosed surface, ans: pi),
6(open surface, ans: -16pi),
7(enclosed surface, outward pointing normal, ans: 2pi)
8, 9,
15(open surface, outward pointing normal, hint: use symmetry to cancel some of the integral),
16(open cone, outward pointing normal),
17(open surface, outward pointing normal, ans: (2*pi*a^3bc)/5, hint: PHI(theta, phi) = a*sin(phi)cos(theta) i + b* sin(phi)sin(theta) j + c*cos(phi) k)
Ch 7 Review 462 7.a-h 1, 3, 4(ans: 0), 5,
6(ans: 8a^2, hint: use symmetry), 7b,
9(hint: x^2+(y/2)^2 = z^2), 10,
12a (ans: sqrt(3)/6),
12b, 13, 15, 16, 17(hint: 7.c.6),
18(open surface, ans: 2pi*r^2), 19, 21,
22(open surface, ans: -15pi/2, can also use Gauss' Thm), 23, 24,
26(open surface, ans: 2pi),
27 (open surface)



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