Course administration:

- Canvas pages (where you must log in):
- face-to-face (Section ES31),
- online (Section WBP01).

- Help with DjVu (if you have trouble reading the files on this page).
- Course policies (TBA).
- Face-to-face class hours: Mondays through Thursdays from 9:00 to 9:50 in ESQ 203.
- Face-to-face class Zoom meeting: 999-4907-1395.
- Face-to-face final exam time: December 16 Wednesday from 9:00 to 10:40 in ESQ 203.

- Name: Toby Bartels, PhD.
- Canvas messages.
- Email: TBartels@Southeast.edu.
- Voice mail: 1-402-323-3452.
- Text messages: 1-402-805-3021.
- Virtual office hours:
- Mondays and Wednesdays from 1:00 PM to 2:00,
- Tuesdays and Thursdays from 10:30 to 12:00, and
- by appointment.

- General review:
- Reading from the textbook: As needed: Review §§11.1–11.5.
- Reading from my notes: Optional: Chapter 1 (through page 17).
- Online notes: Required: Vector operations.
- Exercises due on August 25 Tuesday:
- Give a formula
for the vector
from the point (
*x*_{1},*y*_{1}) to the point (*x*_{2},*y*_{2}). - If
**u**and**v**are vectors in 2 dimensions, then is**u**×**v**a scalar or a vector? - If
**u**and**v**are vectors in 3 dimensions, then is**u**×**v**a scalar or a vector?

- Give a formula
for the vector
from the point (
- Exercises from the textbook due on August 26 Wednesday: 11.2.5, 11.3.1, 11.4.1, 11.4.15, 11.5.23, 11.5.39.

- Parametrized curves:
- Reading from the textbook: Chapter 12 through Section 12.1 (pages 662–668).
- Reading from my notes: Chapter 2 through the first half of Section 2.1 (all of page 19 and the first two lines of page 20).
- Exercises due on August 26 Wednesday:
- If
*C*is a point-valued function, so that*P*=*C*(*t*) is a point (for each scalar value of*t*), then what type of value does its derivative*C*′ take?; that is, is d*P*/d*t*=*C*′(*t*) a point, a scalar, a vector, or what? - If
**c**is a vector-valued function, so that**r**=**c**(*t*) is a vector (for each scalar value of*t*), then what type of value does its derivative**c**′ take?; that is, is d**r**/d*t*=**c**′(*t*) a point, a scalar, a vector, or what?

- If
- Exercises from the textbook due on August 27 Thursday: 12.1.5, 12.1.7, 12.1.9, 12.1.11, 12.1.15, 12.1.17, 12.1.19, 12.1.21, 12.1.23, 12.1.24, 12.1.37.

- Standard parametrizations:
- Reading: Online notes.
- Exercises due on August 27 Thursday:
- For the oriented line segment
from (
*x*_{1},*y*_{1}) to (*x*_{2},*y*_{2}), write down the usual parametrization. - More generally,
for the oriented line segment
from
*P*_{1}to*P*_{2}, write down the usual parametrization. - For the circle in the 2-dimensional plane
whose centre is (
*h*,*k*) and whose radius is*r*, write down the usual parametrization. - If
*f*is continuous function whose domain is [*a*,*b*], write down write down the usual parametrization for the graph of*f*.

- For the oriented line segment
from (
- Exercises from the textbook due on August 31 Monday: 15.1.1, 15.1,3, 15.1.5, 15.1.7.

- Integrating parametrized curves:
- Reading from the textbook: Section 12.2 (pages 671–675).
- Reading from my notes: The second half of Section 2.1 (the rest of page 20).
- Exercises due on August 31 Monday:
If
**f**is a vector-valued function, so that**v**=**f**(*t*) is a vector (for each scalar value of*t*), then:- What type of value
can its definite integrals take?;
that is,
can
∫
^{b}_{t=a}**f**(*t*) d*t*= ∫^{b}_{t=a}**v**d*t*(where*a*and*b*are scalars) be a point, a scalar, a vector, or what? - What type of value
can its indefinite integrals take?;
that is,
can
∫
**f**(*t*) d*t*= ∫**v**d*t*be a point, a scalar, a vector, or what?

- What type of value
can its definite integrals take?;
that is,
can
∫
- Exercises from the textbook due on September 1 Tuesday: 12.2.1, 12.2.3, 12.2.11, 12.2.17, 12.2.21, 12.2.25, 12.2.26.

- Arclength:
- Reading from the textbook: Section 12.3 (pages 678–680).
- Reading from my notes: Section 2.4 (pages 23&24).
- Exercises due on September 1 Tuesday:
Section 12.3 of the textbook uses several variables,
including
**r**,*s*,*t*,**T**, and**v**, to describe various quantities on the path of a parametrized curve. Fill in the right-hand side of each of these equations with the appropriate one of these variables:- d
**r**/d*t*= ___. **v**/|**v**| = ___.- d
**r**/d*s*= ___.

- d
- Exercises from the textbook due on September 2 Wednesday: 12.3.1, 12.3.5, 12.3.8, 12.3.9, 12.3.11, 12.3.14, 12.3.18.

- Functions of several variables:
- Reading from my notes: Chapter 3 through Section 3.1 (pages 27–29).
- Reading from the textbook:
- Chapter 13 through Section 13.1 "Domains and Ranges" (pages 697&698);
- Section 13.1 "Graphs, Level Curves, and Contours of Functions of Two Variables" through the end of Section 13.1 (pages 700–702).

- Exercises due September 2 Wednesday:
- If
*f*(2, 3) = 5, then what number or point must belong to the domain of*f*and what number or point must belong to the range of*f*? - If
*f*(2, 3) = 5, then what point must be on the graph of*f*?

- If
- Exercises from the textbook due on September 3 Thursday: 13.1.3, 13.1.5, 13.1.6, 13.1.8, 13.1.11, 13.1.14, 13.1.16, 13.1.31, 13.1.33, 13.1.34, 13.1.39, 13.1.41, 13.1.43, 13.1.51, 13.1.53, 13.1.59, 13.1.61.

- Topology in several variables:
- Reading from the textbook: Section 13.1 "Functions of Two Variables" (pages 698&699).
- Reading from my notes: Sections 3.2&3.3 (pages 29&30).
- Exercises due September 3 Thursday:
Let
*R*be a relation, thought of as a set of points in**R**^{n}. Recall that a point*P*is in the**boundary**(or*frontier*) of*R*if, among the points arbitrarily close to*P*(including*P*itself), there are both at least one point in*R*and one point not in*R*. For each of the following examples, state whether*R*is open (Yes or No) and whether*R*is closed (Yes or No):- There is at least one point in the boundary of
*R*, and all of them are in*R*. - There is at least one point in the boundary of
*R*, and none of them are in*R*. - There are points in the boundary of
*R*, and at least one of them is in*R*and at least one of them is not. - There are no points in the boundary of
*R*.

- There is at least one point in the boundary of
- Exercises from the textbook due on September 8 Tuesday: 13.1.17, 13.1.19, 13.1.23, 13.1.25, 13.1.27, 13.2.31, 13.2.33, 13.2.35, 13.2.39.

- Limits in several variables:
- Section 13.2 (pages 705–711).
- Reading from my notes: Section 3.4 (pages 30&31).
- Exercises due on September 8 Tuesday:
- Suppose that the limit of
*f*approaching (2, 3) is 5 (in symbols, lim_{(x,y)→(2,3)}*f*(*x*,*y*) = 5), and the limit of*g*approaching (2, 3) is 7 (so lim_{(x,y)→(2,3)}*g*(*x*,*y*) = 7). What (if anything) is the limit of*f*+*g*approaching (2, 3)? (so lim_{(x,y)→(2,3)}(*f*(*x*,*y*) +*g*(*x*,*y*)) = ___). - Suppose that
the limit of
*f*approaching (0, 0) horizontally is 4 (in symbols, lim_{(x,y)→(0,0),y=0}*f*(*x*,*y*) = 4), and the limit of*f*approaching (0, 0) vertically is 6 (so lim_{(x,y)→(0,0),x=0}*f*(*x*,*y*) = 6). What (if anything) is the limit of*f*approaching (0, 0)? (so lim_{(x,y)→(0,0)}*f*(*x*,*y*) = ___).

- Suppose that the limit of
- Exercises from the textbook due on September 9 Wednesday: 13.2.1, 13.2.5, 13.2.13, 13.2.17, 13.2.25, 13.2.27, 13.2.43, 13.2.47, 13.2.59.

- Vector fields:
- Reading from the textbook:
Section 15.2 through "Vector Fields"
(pages 854&855 and Figures 15.7–15.16),
*except*Figure 15.11. - Online notes: Examples of vector fields.
- Exercises due on September 9 Wednesday:
Sketch a graph of the following vector fields:
**F**(*x*,*y*) = ⟨*x*,*y*⟩ =*x***i**+*y***j**;**G**(*x*,*y*) = ⟨−*y*,*x*⟩ = −*y***i**+*x***j**.

- Exercises from the textbook due on September 10 Thursday: 15.2.5, 15.2.47, 15.2.49, 15.2.51.

- Reading from the textbook:
Section 15.2 through "Vector Fields"
(pages 854&855 and Figures 15.7–15.16),
- Linear differential forms:
- Reading from my notes: Chapter 4 through Section 4.3 (pages 33&34).
- Exercises due on September 10 Thursday:
- Given
**F**(*x*,*y*,*z*) = ⟨*u*,*v*,*w*⟩, express**F**(*x*,*y*,*z*) ⋅ d(*x*,*y*,*z*) as a differential form. - Given
**G**(*x*,*y*) = ⟨*M*,*N*⟩, express**G**(*x*,*y*) ⋅ d(*x*,*y*) and**G**(*x*,*y*) × d(*x*,*y*) as differential forms.

- Given
- Exercises
*not*from the textbook due on September 14 Monday:- Evaluate
3
*x*d*x*+ 4*x*^{2}*y*d*y*at (*x*,*y*) = (2, 6) along ⟨d*x*, d*y*⟩ = ⟨0.003, 0.005⟩. (Answer.) - Evaluate
2
*x**y*d*x*+ 2*y**z*d*y*+ 2*x**z*d*z*at (*x*,*y*,*z*) = (−1, 3, 2) along ⟨d*x*, d*y*, d*z*⟩ = ⟨0.01, 0.02, −0.01⟩. - Evaluate
*x*^{2}d*x*+*x**y*d*y*+*x**z*d*z*at (*x*,*y*,*z*) = (4, 3, −2). (Answer.) - Evaluate
5
*x*^{2}d*x*− 3*x**y*d*y*at (*x*,*y*) = (1, 2).

- Evaluate
3

- Differentials:
- Readings from my notes: Section 4.4 (pages 35&36).
- Exercises due on September 14 Monday:
- If
*n*is a constant, write a formula for the differential of*u*^{n}using*n*,*u*, and d*u*. - Write the differentials of
*u*+*v*and*u**v*using*u*,*v*, d*u*, and d*v*. - If e ≈ 2.71828 is the natural base,
then write the differential of e
^{u}using e,*u*, and d*u*. - Write the differential of
ln
*u*= log_{e}*u*using*u*and d*u*. - Write the differentials of sin
*u*and cos*u*using*u*, d*u*, and trigonometric operations.

- If
- Exercises
*not*from the textbook due on September 15 Tuesday:

- Partial derivatives:
- Readings from my notes: Section 4.5 (pages 36&37).
- Reading from the textbook: Section 13.3 through "Functions of More than Two Variables" (pages 714–719).
- Exercises due on September 15 Tuesday:
- If
*f*is a function of two variables and the partial derivatives of*f*are D_{1}*f*(*x*,*y*) = 2*y*and D_{2}*f*(*x*,*y*) = 2*x*, then what is the differential of*f*(*x*,*y*)? (If you're trying to figure out a formula for the function*f*, then you're doing too much work!) - If
*u*is a variable quantity and the differential of*u*is d*u*=*x*^{2}d*x*+*y*^{3}d*y*, then what are the partial derivatives of*u*with respect to*x*and*y*? (If you're trying to figure out a formula for the quantity*u*, then you're doing too much work!)

- If
- Exercises from the textbook due on September 16 Wednesday: 13.3.1, 13.3.2, 13.3.3, 13.3.9, 13.3.11, 13.3.23, 13.3.25, 13.3.29, 13.3.39, 13.3.63.

- Levels of differentiability:
- Readings from my notes: Sections 3.5&3.6 (page 32).
- Reading from the textbook: The rest of Section 13.3 (pages 719–723).
- Exercises due on September 16 Wednesday:
For each of the following statements
about functions on
**R**^{2}, state whether it is always true or sometimes false:- If a function is continuous, then it is differentiable.
- If a function is differentiable, then it is continuous.
- If a function's partial derivatives (defined as limits) all exist, then the function is differentiable.
- If a function's partial derivatives (defined as limits) all exist and are continuous, then the function is differentiable.
- If a differentiable function's second partial derivatives (defined as limits of the first partial derivatives) all exist, then the mixed partial derivatives are equal.
- If a differentiable function's second partial derivatives (defined as limits of the first partial derivatives) all exist and are continuous, then the mixed partial derivatives are equal.

- Exercises from the textbook due on September 17 Thursday: 13.3.43, 13.3.45, 13.3.61, 13.3.85, 13.3.93, 13.3.101.

- Directional derivatives:
- Readings from the textbook:
- Section 13.5 through "Calculation and Gradients" (pages 736–738);
- Section 13.5 from "Functions of Three Variables" (pages 742&743).

- Reading from my notes: Sections 4.6&4.7 (pages 37–39).
- Exercises due on September 21 Monday:
Suppose that ∇f(2, 3) = ⟨3/5, 4/5⟩.
- In which direction
**u**is the directional derivative D_{u}*f*(2, 3) the greatest? - In which directions
**u**is the directional derivative D_{u}*f*(2, 3) equal to zero? - In which direction
**u**is the directional derivative D_{u}*f*(2, 3) the least (with a large absolute value but negative)?

- In which direction
- Exercises from the textbook due on September 22 Tuesday: 13.5.1, 13.5.3, 13.5.5, 13.5.7, 13.5.11, 13.5.13, 13.5.15, 13.5.19, 13.5.23.

- Readings from the textbook:
- Gradient vector fields:
- Readings from the textbook:
- Section 15.2 Figure 15.11 (page 855);
- Section 15.2 "Gradient Fields" (pages 855&856).

- Exercises due on September 22 Tuesday:
- If
*u*=*f*(*x*,*y*), where*f*is a differentiable function of two variables, and d*u*= 2*y*d*x*+ 2*x*d*y*, then what vector field is the gradient of*f*? That is, ∇*f*(*x*,*y*) = d*u*/d(*x*,*y*) = _____. - If
*v*=*g*(*x*,*y*), where*g*is a differentiable function of two variables, and ∇*g*(*x*,*y*) = ⟨*x*^{2},*y*^{3}⟩ =*x*^{2}**i**+*y*^{3}**j**, then what are the partial derivatives of*g*? That is, D_{1}*g*(*x*,*y*) = ∂*v*/∂*x*= ___, and D_{2}*g*(*x*,*y*) = ∂*v*/∂*y*= ___.

- If
- Exercises from the textbook due on September 23 Wednesday: 15.2.1, 15.2.2, 15.2.3, 15.2.4.

- Readings from the textbook:
- Matrices:
- Reading from my notes: Section 1.13 (page 17).
- Exercises due on September 23 Wednesday:
Fill in the blanks with words or short phrases:
- Suppose that
*A*and*B*are matrices. The matrix product*A**B*exists if and only if the number of _____ of*A*is equal to the the number of _____ of*B*. - Suppose that
**v**and**w**are vectors in**R**^{n}. Let*A*be a 1-by-*n*row matrix whose entries are the components of**v**, and let*B*be an*n*-by-1 column matrix whose entries are the components of**w**. Then*A**B*is a 1-by-1 matrix whose entry is the _____ of**v**and**w**.

- Suppose that
- Exercises from an external website due on September 24 Thursday: Take the Mathopolis quiz on multiplying matrices, and send me a message telling me how it went.

- The Chain Rule:
- Reading from the textbook: Section 13.4 (pages 726–733).
- Reading from my notes: Section 4.8 (pages 39&40).
- Exercise due on September 24 Thursday:
If
*u*=*f*(*x*,*y*,*z*) and*v*=*g*(*x*,*y*,*z*), then what is the matrix d(*u*,*v*)/d(*x*,*y*,*z*)? (Express the entries of this matrix using any notation for partial derivatives.) - Exercises from the textbook due on September 28 Monday: 13.4.1, 13.4.3, 13.4.7, 13.4.9, 13.4.41.

- Tangent flats and normal lines:
- Readings from the textbook:
- Section 13.5 "Gradients and Tangents to Level Curves" (pages 740&741);
- Section 13.6 "Tangent Planes and Normal Lines" (pages 744–746).

- Reading from my notes: Section 4.9 (pages 40&41).
- Exercises due on September 28 Monday:
Fill in each blank with ‘line’ or ‘plane’.
- If ∇
*f*(*a*,*b*) exists but is not zero, then*f*has a tanget ___ and a normal ___ through (*a*,*b*). - If ∇
*f*(*a*,*b*,*c*) exists but is not zero, then*f*has a tanget ___ and a normal ___ through (*a*,*b*,*c*).

- If ∇
- Exercises from the textbook due on September 29 Tuesday: 13.5.25, 13.5.27, 13.6.1, 13.6.5, 13.6.11, 13.6.15, 13.6.17.

- Readings from the textbook:
- Linearization:
- The rest of Section 13.6 (pages 747–751).
- Reading from my notes: Section 4.10 (pages 41–44).
- Exercises due on September 29 Tuesday:
- If a function
*f*is to have a good linear approximation in a region, then it's best if its partial derivatives of what order are close to zero in that region? (Its first partial derivatives, its second partial derivatives, its third partial derivatives, or what?) - If (∂
*u*/∂*x*)_{y}= −3 and (∂*u*/∂*y*)_{x}= 2, then is the quantity*u*more or less sensitive to changes in*x*compared to changes in*y*?

- If a function
- Exercises from the textbook due on September 30 Wednesday: TBA.

- More to come.

This web page and the files linked from it were written by Toby Bartels, last edited on 2020 September 25. Toby reserves no legal rights to them.

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