**Chapter 11, Section:**

- 1:
- 2 and 3:
- 4, 5 and 6: None
- 7:

**Chapter 12, Section:**

- 1, 2 and 3: None
- 4:

**Chapter 13, Section:**

- 1:
- 2: None
- 3:
- Differential of a function of two variables Winplot version1, 2, 3, 4,

- 4:
- A surface cut by two vertical planes not parallel to the coordinate planes, and the curves that are cut out Winplot version
- A function
*z = f(x,y)*not defined on the*x-*and*y*-axes, but constant on one line through the origin (so it has a directional derivative on that direction, namely 0) Winplot version - Derivation of the formula for a directional derivative

- 5:
- 6: None
- 7:
- 9:

**Chapter 14, Section:**

- 1:
- 2: None
- 3:

**Chapter 15, Section:**

- 1:
- Approximating the integral: a function and its corresponding "step" function, Winplot version
- Graphics for Page 225, Exercise 13:

- 2:
- 3 and 5: None
- 6:

**Chapter 16, Section:**

- 1, 2 and 3: None

**Chapter 17, Section:**

- 1 and 2:
- A gradient vector field (in Mathematica), and some corresponding contour lines
- Two non-gradient vector fields (in Mathematica), and some corresponding flow lines
- A vector field in Winplot (note that all the nonzero vectors have the same length) Winplot version
- The same vector field in Mathematica, and some corresponding flow lines
- Vector fields for Sec 17.2, Exercise 9 (rotated a quarter turn, for printing purposes)

**Chapter 18, Section:**

- 1 and 2:
- 3 and 4:
- Same as last graphic. Are these vector fields gradients?
- Normals to third vector field in last graphic. Could these flow lines be the contour lines of a function?
- Potential function (?) for Example 4, page 372 Winplot version
- Why Green's Theorem is true