Math 151

Math 151

Exam 3

Spring 2006


100 points possible.


1. (10 pts.) Let f(x)=x3-9x2-48x+5. Find the absolute maximum and absolute minimum values of f on the interval [-4,3].

2. (10 pts.) Verify that the function satisfies the hypotheses of the Mean Value Theorem on the given interval [a,b]. Then find all numbers c such that
f¢(c)= f(b)-f(a)
b-a
.


f(x)=x3+7x,       [-6,2]

3. (15 pts.) Given:
f(x) = unknown continuous function, with domain the set of all real numbers

f¢(x) = (7x+4)(x+4)5,             f¢¢(x) = 6(7x+8)(x+4)4

(a) Find the critical numbers of f.

(b) Find the intervals on which f is increasing or decreasing.

(c) Find the x-coordinates of all local maxima and local minima of f.

(d) Find the intervals of concavity.

(e) Find the x-coordinates of all points of inflection.

4. (10 pts.) Find the following limits exactly. Provide all major algebraic/symbolic steps to justify that your answer is correct.


(a)

lim
x® +¥ 
1-3x-4x2
11x2-7

(b)

lim
x® +¥ 
12x3+11
  _______
Ö7x6+5x

5. (15 pts.) Given:
f(x) = 18x4-134x3+175x2+632x+852,

f¢(x) = 72x3-402x2+350x+632,

f¢¢(x) = 216x2-804x+350.
Use a graphing calculator to estimate these answers to two decimal places.


(a) Find the critical numbers of f.

(b) Find the intervals on which f is increasing or decreasing.

(c) Find the x-coordinates of all local maxima and local minima of f.

6. (10 pts.) A piece of wire 20 meters long is cut into two pieces. One piece is bent into a square, and the other is bent into a rectangle whose length is twice its width. How should the wire be cut so that the total area enclosed is (a) a maximum? (b)  a  minimum?

7. (10 pts.) Use Newton's method to find the root of the given equation to the best accuracy your calculator will display. Use the specified initial approximation  x1, and show your values for x2, x3, x4, and so on, until the algorithm stabilizes.
2x3+x2-x+1=0,       x1=-1.2
Recall that
x2=x1- f(x1)
f¢(x1)
and
xn+1=xn- f(xn)
f¢(xn)
.

8. (10 pts.) Find the most general antiderivative of the given function.


(a)
f(x)=sec2 x

(b)
f(x)= 25x2+8
x5

9. (10 pts.) Find f(x), given the following.



f¢¢(x)=36x2-12x+10,       f(2)=5,     f¢(2)=4




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