<p>IndianJatt</p>
<p>what i remember is
1.
(a) -0.1mile/min</p>
<p>i got that</p>
<p>(b) Distance Caren traveled from home to school. 1.4 is the answer to the integral.</p>
<p>I got 1.8 i think…I believe since it was total distance you were supposed to take the absolute value</p>
<p>(c) Caren closer lives. LOL I did that on purpose the switch of words.</p>
<p>**That wasn’t C. C asked when she turned around to go home…which was at t=2. </p>
<p>Then for D I got that they lived the same distance. Cause Caren’s total trip took 1.8 miles and Larrys took 1.6…but Caren spent .2 miles going back home so she actually only lives 1.6 miles away**</p>
<p>2.
(a) 980
(b)x= 2.044
(c) 387.5</p>
<p>I’m pretty sure I got similar answers to all of those?</p>
<p>(d) Explain please and I will see if I got credit or not. </p>
<p>you just take C and divide by A, i think it was like .776 or something to that effect</p>
<p>3.
(a) 2970</p>
<p>i think i got 2500</p>
<p>(b) … same as d</p>
<p>**i think it means the cost of a cable from meter 25 to 30 or a 5 meter long cable or something like that</p>
<p>i don’t remember any of my other answers**</p>
<p>6
a. it has a point of inflection at x = 0 and x = -2</p>
<p>Are you freaking serious? Ughhh it clearly says “The rate at which people enter an auditorium for a rock concert is modeled by the function R given by
R(t) = 1380t2 - 675t3 for 0 £ t £ 2 hours;”</p>
<p>THE RATE, c’mon the RATE means the derivative meaning that that equation did not need to be differentiated and all that was needed is to set it equal to 0. So i set that equal to 0 and it SHOULD be the maximum. But nope, they have ****ty wording and I didn’t realize 2.044 was outside the range. I put 2.044 too, but I guess it’s wrong… So stupid. Bleh, it’s only one question, an easy question. Oh well</p>
<p>Btw for 2d I got .77551 of an hour</p>
<p>I took the integration from part c and instead of 1 to 2 used 0 to 2 and then divided it by the answer in part A. Is that how everyone else did it?</p>
<p>How do you do 3d? I had like 5 minutes to do all of #3 lol and I just rushed it. I know I got a, b and c, though. I don’t feel like thinking.</p>
<p>I am positive Caren lives closer. If you don’t include the time it takes her to get her calculus book, you will get the distance it takes her to get to school, which is 1.4. and the other persons is 1.6.</p>
<p>3(a)…How can it not be $2970. Think about it.</p>
<p>“(Note: Profit is defined to be the difference between the amount of money received by the company for selling
the cable and the company’s cost of producing the cable.)”</p>
<p>They tell you exactly how to get the profit. So the fixed length is 25 meters, which is 120(meters)-6root(meters)=120(25)-6(5)=2970</p>
<p>selter01, 2(b) I think it is right, but when reading azn comment, I am worried about maybe that interval. o.o </p>
<p>The RATE is the DERIVATIVE, meaning to find the maximum, you set the rate = to zero.</p>
<p>Selter01, 6(a) has a point of inflection at x=0, because we are given the graph of f’(x), which means that the maximums of f’(x) will be your possible points of inflections. Since the signs of the slopes are different, which is also how the graph of f’‘(x) is shaped since the slope is found using the derivative of f’(x) somehow, you get a POI.</p>
<p>I got what selter01 got, why isnt it P(t)= 120k - int( 6sqrt(k)) from 0 to k…???</p>
<p>and I also got 16,000 as profit max</p>
<p>"3(a)…How can it not be $2970. Think about it.</p>
<p>“(Note: Profit is defined to be the difference between the amount of money received by the company for selling
the cable and the companys cost of producing the cable.)”</p>
<p>They tell you exactly how to get the profit. So the fixed length is 25 meters, which is 120(meters)-6root(meters)=120(25)-6(5)=2970"</p>
<p>You have to take the definite integral of 6root(meters) from 0 to 25.</p>
<p>I just found out that on question one,
Caren travels 1.8 mile,
and as a result, Caren and Larry live at the same distance away from school</p>
<p>For 3a, I have $2500, too.
for 3b, my answer was over $100. i wrote that this was loss of profit when selling 30 meter cable compare to 25 m.</p>
<p>caren lives closer; ignore the 2 triangles at first and find the area</p>
<p>Chemfromma, yea i integrated to k
P(t)= 120k - int( 6sqrt(x)) from 0 to k…???</p>
<p>jerrry4445 you are making a mistake with Caren and Larry. Here is what you are doing. You are using your answer from part b, which says take the absolute value, which means you counted her trip back home as a distance of .2, which gave you .2+.2+1.4 and you got 1.8. The only reason it took her 1.8 miles to get to school, was because she headed back home and went back. Say she didn’t go back home, her distance to school is 1.4 miles. and also how did you get 1.8. It says Larry’s velocity is pi/15sinpi/12*x, and to find the distance traveled you take the integral, which gives the distance he traveled and it is 1.6 miles.</p>
<p>Correct Answers:
- a. -.1 m/sec2
b. 1.8 meters
c. t=2
d. Caren=1.4 miles<Larry=1.6 miles </p>
<p>sorry, its 1.8 miles for b</p>
<p>ya, it makes sense, if profit is defined by income (120k) minus the costs (int( 6sqrt(x)) from 0 to k), where k is any legnth of rope, then the equation that we both got should work for the profit attained for any k> or = to 0…</p>
<p>man i got 1.4…So I bet 0 points for b, and for c what if I wrote (2,4) and gave the reason that she headed back home from 2 minutes to 4 minutes because that at 2 minutes she changed her direction of travel since it is below the x axis or something. Can i get partial credit for that?</p>
<ol>
<li>a. 980 people
b. 1.363=t
c. 387.5 hours
d. 0.776 hours</li>
</ol>
<p>**** now I see why b is wrong. You have to find when the RATE is maximum, not when the number of people is maximum. ■■■</p>
<p>wait so its agreed that the integral from 0 to 12 for Caren was 1.8?
and that the integral 2 to 4 (of going back home) was .2 (the area of the triangle=.2 x .5 x 2)?</p>
<p>so wouldnt the total distance of 1.8-the going back home distance of .2=the actual distance to school for Caren?</p>
<p>Any guesses on 4 b? The area between the curves where the cross sections are sin(x*pi/2)?</p>
<p>I got 2/pi, but I kind of pulled it out of nowhere…</p>