Calculus 1  Hour Exam 2  (continued) -   Math 221     Fall, 2011

 

 

 

 

 

 

 

 

6.

 

 

 

The graph of a function  y = f(x) and a point  x1  are shown below.  Using Newton’s

method on  f  with initial approximation  x1,  mark on the x-axis where  x2  will be

and briefly explain how you found  x2.  One sentence should be enough.

 

                        

 

 

 

7.

 

Gravel is being dumped from a conveyor belt at a rate of 30 ft3/min, and its coarseness

is such that it forms a pile in the shape of a cone whose base, diameter, and height are

always equal.  How fast is the height of the pile increasing when the pile is 10 ft high?

 

Answer:   6 / 5π   ft/min

 

 

 

 

8.

 

 

A bacteria culture initially contains 100 cells and grows at a rate proportional to its size.

after an hour the population has increased to 420 cells.  Find an expression for the

number of cells after  t  hours.

 

Answer:  y  =  100 e (ln 4.2) t

 

 

 

 

 

9.

 

 

A graph of  y  =  f(x)  is given (not shown). 

 

a.        On what intervals is  f  increasing and on what intervals is  f  decreasing?

b.        On what intervals is  f  concave up and on what intervals is  f  concave down?

c.        At what  x-value does  f  have the largest rate of increase?

 

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