Honors AP Calculus / Mr. Hansen

Name: ______________KEY_____________________

10/12/2006

Mr. Hansen’s use only (bonus point for spare batteries): _______

 

Test on Chapters 2 and 3

 

1.

C

2.

E (General antiderivative is x3 − 3.5x2 + C, and the one which makes f (1) = 2 is f (x) = x3 − 3.5x2 + 4.5. Then plug in to get the answer.)

3.

D (The expression in parentheses is a constant.)

4.

D (Use a difference quotient.)

5.

A (Generalize result from #4, then perform algebra. Students seem to find this problem to be either easy or extremely difficult.)

6.

B by definition of derivative (limit of difference quotient)

7.

B

8.

C (intersections give delta of .003741019 on the left, .0037270759 on the right; always remember to round down)

9.

C (can get by process of elimination)
A is not possible since N(2) = 0 by inspection, and N(4) = 110/3 (given).
B is acceptable (and in fact I allowed it for credit) but is not the best answer. See #10 for a hint.
D makes no sense.
E is enticing, except that any antiderivative of t2 + 3t is of the form  which is a function of t, not a function of x.

10.

A

11.

The proposed definition is acceptable. (Remember that the secants must be able to stretch either to the left or to the right. Otherwise we would have only a one-sided derivative.) The derivative value, , can also be thought of as the slope (iff such slope exists and is uniquely defined) of a tangent to the curve at (c, g(c)), or as the instantaneous rate of change of the function g at the point x = c. However, these “ways of thinking” of  are not fully rigorous. You could also give either or both of the two standard (fully rigorous) definitions using difference quotients:

 

 

12.

iff (or “if and only if”)

 

 

<

 

 

13.

Since infinity is not a number, it is nonsense to speak of “approaching infinity.” Strictly speaking, the notation  should be replaced by the words “as x increases without bound.”

 

 

14.

(a)  Graph should resemble a sinusoid, except with a vertical asymptote at t = 0 and decreasing amplitude as t increases. The centerline should be shown to be above the t axis (ideally at D = 4), but no detail was required. Any vaguely sinusoidal squiggle with decreasing amplitude and centerline above 0 will qualify.

 

(b)  4 (since second term vanishes as t grows without bound)

 

(c)  If M = 10,000, then t > M implies that the second term is



which is bounded by 0.1 in absolute value since the cosine of any value has range [−1, 1]. The presence of a strict inequality earlier in the chain makes the final inequality strict; i.e., the second term is strictly bounded by the open interval (−.1, .1).

 

 

 

      D(t) is differentiable on the positive reals, hence certainly continuous for all values of t > 10,000. Therefore, as long as t > 10,000, the sum of 4 and the second term is strictly bounded by the interval (3.9, 4.1). (Q.E.D.)

 

 

 

(d)  You can always use  for this function. Proof (optional) is as follows:

If t > , then the second term’s absolute value is

.

(Q.E.D.)

 

 

15.

 

 

16.

 

 

17.