Here is material about the administration of the course:

- Canvas page (where you must log in for full access, available while the course is in session).
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- Course policies (DjVu).
- Class hours: Mondays through Thursdays from 1:00 PM to 1:50 in ESQ 100C.

- Name: Toby Bartels, PhD;
- Canvas messages.
- Email: TBartels@Southeast.edu.
- Voice mail: 1-402-323-3452.
- Text messages: 1-402-805-3021.
- Office hours:
- Mondays and Wednesdays from 9:30 to 10:30,
- Tuesdays and Thursdays from 2:30 PM to 4:00, and
- by appointment,

- Chapter 1 (on vectors);
- Chapter 2 (on parametrized curves);
- Chapter 3 (on functions of several variables);
- The full set.

- General review:
- Date due: January 14 Tuesday.
- 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:
- 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 (

- Parametrized curves:
- Date due: January 15 Wednesday.
- 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:
- 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

- Integrating parametrized curves:
- Date due: January 16 Thursday.
- 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:
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
∫

- Arclength:
- Date due: January 21 Tuesday.
- Reading from the textbook: Section 12.3 (pages 678–680).
- Reading from my notes: Section 2.4 (pages 23&24).
- Exercises due:
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

- Functions of several variables:
- Date due: January 22 Wednesday.
- 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:
- 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

- Topology in several variables:
- Date due: January 23 Thursday.
- 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:
Let
*R*be a (binary) 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

- Limits in several variables:
- Date due: January 27 Monday.
- Section 13.2 (pages 705–711).
- Reading from my notes: Section 3.4 (pages 30&31).
- Exercises due:
- 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

- Vector fields:
- Date due: January 28 Tuesday.
- 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:
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**.

- Linear differential forms:
- Date due: January 29 Wednesday.
- Reading from my notes: Chapter 4 through Section 4.3 (pages 33&34).
- Exercises due:
- 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

- Differentials:
- Date due: January 30 Thursday.
- Readings from my notes: Section 4.4 (pages 35&36).
- Exercises due:
- 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

- Partial derivatives:
- Date due: February 3 Monday.
- 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:
- 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

- Levels of differentiability:
- Date due: February 4 Tuesday.
- 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:
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.

- Directional derivatives:
- Date due: February 5 Wednesday.
- 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:
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

- Gradient vector fields:
- Date due: February 11 Tuesday.
- Readings from the textbook:
- Section 15.2 Figure 15.11 (page 855);
- Section 15.2 "Gradient Fields" (pages 855&856).

- Exercises due:
- 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

- Matrices:
- Date due: February 12 Wednesday.
- Reading from my notes: Section 1.13 (page 17).
- Exercises due: 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

- The Chain Rule:
- Date due: February 13 Thursday.
- Reading from the textbook: Section 13.4 (pages 726–733).
- Reading from my notes: Section 4.8 (pages 39&40).
- Exercise due:
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.)

- Tangent flats and normal lines:
- Date due: February 18 Tuesday.
- 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:
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 ∇

- Linearization:
- Date due: February 19 Wednesday.
- The rest of Section 13.6 (pages 747–751).
- Reading from my notes: Section 4.10 (pages 41–44).
- Exercises due:
- 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

- Local optimization:
- Date due: February 20 Thursday.
- Reading from my notes: Section 4.11 (pages 44&45).
- Section 13.7 through "Derivative Tests for Local Extreme Values" (pages 754–758).
- Exercises due:
Consider a function
*f*of two variables that is defined everywhere. Identify whether*f*has a local maximum, a local minimum, a saddle, or none of these at a point (*a*,*b*) with these characteristics:- If the partial derivatives of
*f*at (*a*,*b*) are both negative. - If one of the partial derivatives of
*f*at (*a*,*b*) is zero and the other is negative. - If both partial derivatives of
*f*at (*a*,*b*) are zero and the Hessian determinant of*f*at (*a*,*b*) is negative. - If both partial derivatives of
*f*at (*a*,*b*) are zero, the Hessian determinant of*f*at (*a*,*b*) is positive, and the unmixed second partial derivatives of*f*at (*a*,*b*) are negative. - If both partial derivatives of
*f*at (*a*,*b*) are zero, the Hessian determinant of*f*at (*a*,*b*) is positive, the unmixed second partial derivatives of*f*at (*a*,*b*) are positive, and the mixed second partial derivatives of*f*at (*a*,*b*) are negative.

- If the partial derivatives of

- More to come!

This web page and the files linked from it were written by Toby Bartels, last edited on 2020 February 18. Toby reserves no legal rights to them.

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