1.       a. State a viable definition (viz, it works) for the statement: Quantity A changes at a constant rate with respect to Quantity B.  What is most subtle about the meaning you gave?

 

 

 

 

 

 

 

 

b. Interpret this statement: At x = 3.4 and y = 5.1, a non-linear function k(x,y) has average rates of change of -2 in the x direction and +3 in the y direction over intervals of length 0.001.

 

 

 

 

 

 

 

 

 

 

 

c. What does the graph of k look like in the immediate region of the point (3.4, 5.1, k(3.4,5.1))?

 
 


2.       Values of the function f approximate the amount of water that has flowed out the mouth of the Amazon (out to sea is positive) over a particular time span.
The function
r, whose graph is at the right, gives the average rate of change of f over intervals of length 1 second. The vertical axis is billions of cubic meters per hour. The horizontal axis is number of days.

 

a)      What does the point (0.41,-0.81) on this graph of r represent?

 

 

 

 

b)      Interpret the graph of r. What is it showing?

 

 

 

 

 

 

 

 

c)      Sketch a graph of f over the period of time captured by the graph of r. Use billions of cubic meters for your vertical axis and numbers of days as your horizontal axis.

 

 

 

 

 

 

 

 

 

 

d)      Explain your graph to someone who understands accumulations but is unaware of how you got this graph.


3.       Give an argument for the claim that any function having a plane as its graph is of the form f(x,y) = nx + my + K. Use illustrations as appropriate.

60 points

 
 

 

 



4.       Here are graphs of z = x2y – 4cos(xy)+4 and z = 2, -3 ² x, y ² 3. The coordinate system is oriented with x to the right and z up.

 

 

 

 

 

 

 

 

a)      Sketch the solution set[1] to the equation x2y – 4cos(xy)+4 = 2.

 

 

 

 

 

 

 

 

b)      How, in principle, did you know where to draw your solution set?

 



[1] The solution set of an equation is the set of all elements in the functionÕs domain that make the equation true.