Math 132, Calculus 2, Exam 2 Practice Problems
Tom Linton, Spring 2002
The following questions contain many of the important concepts for our
second exam. This practice sheet is by no means a complete list of the
topics you should know, it is simply a collection of problems to help prepare
you for the exam. Most likely, none of these questions will appear on the
exam, but if you can do all of these problems without much trouble, you
should be well prepared for the test.
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Three cars ran a race and their velocities are given below. The race was
200 feet long and the velocities are given in feet per minute. The first
car, car 1, had a velocity of 1000sin(0.65t2) feet per minute,
t minutes into the race. The second car had the velocities given in the
table below.
Car 2 Velocities
| Time (min) |
0.0 |
0.1 |
0.2 |
0.3 |
0.4 |
0.5 |
0.6 |
0.7 |
0.8 |
0.9 |
1.0 |
| Velocity ( ft /min) |
0 |
43 |
82 |
118 |
151 |
182 |
211 |
238 |
264 |
289 |
312 |
The third car's velocities are plotted below.
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For car 1, would TRAP(n) over-estimate or under-estimate the distance traveled
by car 1 from t = 0 to t = 1 minutes? Explain.
-
For car 1, would MID(n) over-estimate or under-estimate the distance traveled
by car 1 from t = 0 to t = 1 minutes? Explain.
-
Verify that car 1 finishes the race between t = .98 minutes and t = .99
minutes using TRAP(100) and MID(100). Explain your reasoning.
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For car 2, clearly explain, using LEFT(10) or RIGHT(10), why car 2 did
not win the race.
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What does MID(5) give for an estimate of the distance traveled by car 2
from t = 0 to 1 minutes? Is this estimate too big, or too small? How do
you know?
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Calculate the exact time that car 3 finishes the race.
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Who won the race?
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Evaluate each of the integrals below, using the Fundamental Theorem (i.e.
do not use fnInt to do any of the definite integrals) and show your work.
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-

-

-

-

-

-

-

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Consider
,
where a graph of f(x) is shown below. Use the graph to answer the following
questions.
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Estimate values for LEFT(4), RIGHT(4), MID(4), TRAP(4) and SIMP(4) for
this integral.
-
Draw in the rectangles used to calculate MID(4).
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Which of your estimates are guaranteed to be over-estimates? Which are
guaranteed to be under-estimates? For which estimates can you not tell
for sure whether they are under or over-estimates?
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It turns out that, for the integral above, MID(8) = 11.514 and MID(16)
= 11.4944. Assume that the error in MID(16) is exactly one-fourth the error
in MID(8). Use this assumption to give a better estimate of
.
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Consider
.
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Verify that this integral is improper. Explain why LEFT(n), RIGHT(n), and
TRAP(n) cannot be used directly to estimate this integral.
-
Even fnInt will have trouble with this integral (try it, if your
calculator simply stays busy for a long time, press the [ON] key to quit
the calculation). To estimate this integral, we will cut it into two pieces,
namely I1 =
and I2 =
.
Which of LEFT(n) or RIGHT(n) could be used to estimate I1? Which
of LEFT(n) or RIGHT(n) could be used to estimate I2? Explain.
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Verify that
=
(that is,
show that I1 = I2). HINT: make the substitution
u = 1 - x, and completely transform I1 into terms of u.
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Part (c) says that
= 2
, so we only
need to estimate
,
and double it's value. The trouble spot is x = 0, since f(0) is undefined.
This means we cannot use LEFT(n) (so our program won't run), nor can we
use TRAP(n) (since it uses LEFT(n)). To remove this trouble spot, we need
to estimate
,
and then we could use any of our estimates from x = 1 / (2n) to x = 1 /
2. I chose the upper bound of integration to be 1 / (2n), since that corresponds
to using n rectangles from x = 0 to x = 1 / 2. Show (by hand) that using
one midpoint rectangle to estimate
gives the estimate
.
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Evaluate the estimate from part(d) for n = 50. We can now estimate
using any of our methods by adding the part(d) estimate for n = 50, to
what we get (for example) by using LEFT(49) from x = 0.01 to x = 0.5. Use
this idea to give left, right, mid, trap and simp like estimates for
for "n = 50".
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Between which two of your estimates from teh last part does the true value
of the integral lie? Double your best estimate to give an estimate for
the original integral from x = 0 to x = 1.
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Now we'll calculate the exact value of I =
.
Draw a right triangle with hypotenuse 1, altitude square root of x, and
adjacent side length square root of 1 - x. Name the lower left angle q.
Show that this triangle gives the substitution x = sin2(q).
Use the triangle to completely transform the integral I into terms of q.
Evaluate the resulting integral (it is easy) to calculate the exact value
of the integral I.