Tuesday, 19 April 2005
Attempt all of the following questions; there are 11 problems, for a total of 120 points. The
total time available is three hours (180 minutes).
1. (8 points)
(a) Use tensor notation
SIMON FRASER UNIVERSITY
DEPARTMENT OF MATHEMATICS
Midterm solutions, both versions
MATH 252 D100 Spring 2013
Feb. 20, 2013, 8:30 9:20 a.m.
A summary of Friday's lecture was given [Transparancy 1], showing the definitions
of curvature, unit tangent vector, principal normal, tangential acceleration, and normal
A detailed example was worked out [Transparancies 2 and
Last lecture we proved the first vector identity in section 1.14 of the textbook, using
tensor notation. In this lecture, we proved the other three vector identities of section
1.14 [Transparancies 1 and 2]. (In Assignment #02, you are asked to prove thes
We continued with our discussion of polar coordinates in the xy-plane [Transparancy
1]. The acceleration vector was obtained by differentiating the velocity vector, and
being careful about differentiating the radial and angular unit vectors. Four differen
Section 4.1: Line Integrals
1. Recall Arc Length:
|R (t)|dt =
2. Arc Length in Curvilinear Coords.
3. Example in Cylindrical: arc length of a portion of the helix given by
() = e + e + cos( + )k.
Sections 4.2 and 4.3 Notes
1. Basic Concepts from Topology
(b) interior point of a set
(c) boundary point of a set
(d) exterior point of a set
(e) open set: every point is interior
(f) connected (arcwise): any two points can be joined b
Section 4.4: Fields with Curl Zero
1. Fields with curlF = 0 are called irrotational. (Fluids context).
2. Theorem If F is continuously dierentiable in a region D R3 , then F is conservative
(i.e. F = grad) i curlF = 0.
( i) F ind a n i rrotational field F having a specified divergence p.
Let be defined by (13) and let F : = ' 7.
( ii) Find a scalar potential for field F in ( i)
(iii) Find a solenoidal field F in a domain D having a spcefied curl . ) Note
Tutorial 9-Math 252
1. If x2 y + yz = 0, xyz + 1 = 0, nd dx and dz at (x, y, z ) =
(1, 1, 1).
2. If x2 + yu + xv + w = 0, x + y + uvw + 1 = 0, then regarding
x and y as functions of u, v, and w, nd
at (x, y, u, v, w) = (1, 1, 1, 1, 1).
Now we will begin to look at vector derivatives. The rst of these is the divergence of a
1. Denition. Given a vector eld F , its divergence is
F1 F2 F3
presuming those partial derivatives exist.
3.4 to 3.6: Curl and the Laplacian
1. Denition of Curl
2. Standard Examples
3. Product Rule.
curl(F ) = curlF + grad F .
4. Paddle Wheel Analogy
Figure 1: From http:/www.instrumart.com/pages/227/in-line-turbine-paddle-wheel-owmeters.
Reminder: Near a p
1. Recall the divergence theorem in the form
F dV =
where D is closed and S is the boundary of D.
2. Recall also the vector identity
( ) =
whose proof is not hard.
3. Let F = and apply the divergence theorem:
4. Greens rst
Section 4.7 - 4.9: Surface and Volume Integrals
1. Surface Integral of a scalar function
2. Surface integral of a vector function: surface given parametrically (use of R/u
3. Using rectangular coordinates
5. Physical Example
Sections 4.5 Notes
1. Vector Potentials
If F is a vector eld (i.e. vector-valued function) such that F =
G, then G is
called a vector potential for F .
Theorem: Suppose F is continuously dierentiable in D R3 , where we will assume
D is star-shaped in our
We started off [Transparancy 1] by considering the velocity vector when the
magnitude of the position vector stays constant. It was shown that the velocity vector
is perpendicular to the position vector under these circumstances.
We then looked in some de
We started looking at acceleration and curvature along a spacecurve (section 2.3 of
the textbook). Acceleration has two components [Transparancy 1], tangential and
centripetal. The latter is defined in terms of a radius of curvature. The curvature
Due 9:00am Friday Feb 27
1. (a) Write e , e , ez at point P = xe1 + ye2 + ze3 in terms of (x, y, z) and
e1 , e2 , e3 .
yi + xj
. Write F in terms of the cylindrical coordinates and
x2 + y2
compute the divergence and curl of F using both the
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