Answer each of the following questions by drawing a schematic diagram.
a. Taking measurements of the slope of a curve at three points farther and farther to the right along the horizontal axis, the slope of the curve changes from $-0.3,$ to -0.8 to $-2.5,$ measured by the point method. Draw a schematic diagram of this curve. How would you describe the relationship illustrated in your diagram?
b. Taking measurements of the slope of a curve at five points farther and farther to the right along the horizontal axis, the slope of the curve changes from $1.5,$ to $0.5,$ to 0 to $-0.5,$ to $-1.5,$ measured by the point method. Draw a schematic diagram of this curve. Does it have a maximum or a minimum?