AP BC CALCULUS THURSDAY 5/8

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Discus: SAT/ACT Tests and Test Preparation: May 2003 Archive: AP BC CALCULUS THURSDAY 5/8
 By Clangpants1 (Clangpants1) on Thursday, May 08, 2003 - 02:29 pm: Edit

I took the exam... The MC wasn't bad, but the long answers were awfully hard.... Anyone with thoughts or answers?

 By Heatwave345 (Heatwave345) on Thursday, May 08, 2003 - 03:09 pm: Edit

Yeah

I though that the free-response questions were really hard and i made so many mistakes. Hopefully, i'll still get a 5. *fingers crossed*

what did you guys get for the question in Section I Part A about the coefficient of x^2.

 By J_Jay (J_Jay) on Thursday, May 08, 2003 - 03:17 pm: Edit

uh i got 3 im not sure tho

 By Nocalguy (Nocalguy) on Thursday, May 08, 2003 - 04:02 pm: Edit

How do you they grade the free response? If you get part a) wrong, do they still give you full credit on part b) and c) if you use your answer from part a) to find them as long as the work you did in part b) and c) are correct?

 By Jk9903 (Jk9903) on Thursday, May 08, 2003 - 04:12 pm: Edit

Yeah, the MC wasn't too hard at all. The FR was tricky, I definitely didn't expect to see polar equations surface on a FR problem, and I didn't really study them (did it independent), but I think I did it alright. All my other answers are matching with other posters', so I think I'm alright. FR #2 was a weird question however...I think the distance from A-D was like 39.5

 By J_Jay (J_Jay) on Thursday, May 08, 2003 - 04:33 pm: Edit

yeah it was 39.5, u had to take the integral of dx/dt from from 0 to 9

 By J_Jay (J_Jay) on Thursday, May 08, 2003 - 04:37 pm: Edit

does ne1 remember what they got for the very last question on part 1 section b? it asked wen the average rate of change was equal to the instantaneous rate x=c?? it was of Y= X lnX

 By Quarky (Quarky) on Thursday, May 08, 2003 - 04:42 pm: Edit

Mult choice wasn't too bad. FR was pretty hard.

ABCD points stuff -- I messed up on the velocity+speed questions, but got the first part and the last part (39.5) right. So I prolly got 3-4 points here.

Line+ semicircle defined by y=sqrt(4- (x-2)^2) - 2 was really easy. Probably got 9 points there.

Cylinder coffee jug thingy was pretty easy, although it took me like 10 mins to figure out that i simply plug 5 in for r BEFORE deriving V'. My classmates didn't get this prob at all, cause all of them said V'=2Pir*dh/dt = 2*Pi*5*dh/dt
I finally understood it was V = Pi*25*h, V' = 25Pi dh/dt. Got 9 points here, I think.

e^-3x or whatever and that other function... form some region and stuff. Pretty easy. I got 7-8 points.

Power series -- I didn't know ANYTHING about it (the entire BC part was self-taught for me, so that was pretty hard). I got the right formula for f' in terms of x and n, but I think i made a small mistake for f''. I correctly explained why the error was less than 1/100 (it was less than 1/120). I think i got around 4 points here.

The polar stuff -- no chance. I didn't get it. I just wrote doen the fromula for area, but did not specify the limits of integration because I ran out of time and couldnt use the calculator to graphically find the limits. ~5 points on this problem for getting the intersection points and the area integral in terms of y.

So I should have gotten at least 35 points on the FR.. prolly around 30-35 on MC. those MC are multiplied by 1.2 to equal 50% of the total points, so I think I got around 70 points total, out of 108. What grade is this gonna be?

 By Clangpants1 (Clangpants1) on Thursday, May 08, 2003 - 04:53 pm: Edit

how did you do the line and semicircle, part d, where it said find f(4) and f(-3)?

I am so stupid, how do with the volume of the e^-3x and some other curve around y=1?

Quarky, I would guess 70 is a 5.

 By Quarky (Quarky) on Thursday, May 08, 2003 - 04:57 pm: Edit

Do you have a messenger? MSN is preferred. I will tell u then...

 By Heatwave345 (Heatwave345) on Thursday, May 08, 2003 - 05:03 pm: Edit

=====================================================
how did you do the line and semicircle, part d, where it said find f(4) and f(-3)?
=====================================================

f(x)=integral(f'(x)) (obviously!!!)

f(a)-f(b)=integral(f'(X),a,b)

so.....
f(4)-f(0)=integral(f'(x),0,4)

f(0)=3 and you can find the integral of by subtracting the semicircle from the rectangle(imaginary)

Ditto for f(-3)

===================================================
how do with the volume of the e^-3x and some other curve around y=1?
===================================================

this is how i set it up

Pi * integral((1-e^(-3x))^2-(squrt(x))^2,0.238,1)

 By Clangpants1 (Clangpants1) on Thursday, May 08, 2003 - 05:03 pm: Edit

yes..... msn: spackle24@hotmail.com

 By Nocalguy (Nocalguy) on Thursday, May 08, 2003 - 05:03 pm: Edit

Clangpants,the net area under the derivative curve that they give you shows the net change in f(x). Once you have that, you can use that and the one point they do give you to find the y value at x=4 and -3.

 By Nocalguy (Nocalguy) on Thursday, May 08, 2003 - 05:05 pm: Edit

I thought the MC part was easy and also Part B of the FR. Hardest part for me was Party A of the FR.

 By Quarky (Quarky) on Thursday, May 08, 2003 - 05:10 pm: Edit

Clangpants -- u r offline with MSN messenger...

Heatwave-
That e^(-3x) deal... i got a diff answer, but here is how I did it.

The region R is revolved around y=1. That results in the same volume as region R-1 (shifted down one level) created around y=0 (x-axis).

So if we have f=e^(-3x)-1 and g=sqrt(x)-1 and revolve them around x-axis, we get the same volume, right?

I had Pi*int(f^2) - Pi*int(g^2) with respect to X with limits of integration .238 and 1. Do u think they will give me full points for doing this

 By Heatwave345 (Heatwave345) on Thursday, May 08, 2003 - 05:20 pm: Edit

Quarky

they yield the same answer, so you should get full credit.

 By Quarky (Quarky) on Thursday, May 08, 2003 - 05:28 pm: Edit

good

 By Nunchaku (Nunchaku) on Thursday, May 08, 2003 - 05:36 pm: Edit

for the line and semicircle thing, i found the value of f'(x) at the point they were asking (f(4) and f(-3)), which gave me the slope.

then, since they gave us the info that f(0)=3, i used the slope to find the tangent line equations, then plugged in the value of x they were asking for to find f(4) and f(-3)... is that right? also, for the increasing interval, was it (-3,0) or [-3,0]? (i dont remember if those were the numbers, but im wondering if the endpoints were included)

for the area revolved around y=1, isnt it the integral of (1-e^-3x)^2 - (1-root(x))^2 (i dont remember the bounds).

 By Heatwave345 (Heatwave345) on Thursday, May 08, 2003 - 05:36 pm: Edit

which of the following diverges?

summation from n=1 to infinity of the following

I. (sin2/PI)^n

II. (1/n^(1/3))

III. (e^n/(e^n+1))

i'm pretty sure that both I and II diverges, but what about III?

 By Heatwave345 (Heatwave345) on Thursday, May 08, 2003 - 05:40 pm: Edit

do you guys think this thread will beat the MAY SAT thread???

LOL jk

 By Brd (Brd) on Thursday, May 08, 2003 - 06:22 pm: Edit

Heatwave: As you wrote it, I. does converge -- it is simply a geometric series, since |sin(2/PI)| < 1

Mathematica says II. diverges. That was also my guess, but I am too lazy to prove it at the moment since the ratio test turns out not useful to be in this case.

And III. diverges since the limit of the individual terms is not zero.

 By Kaimeluin (Kaimeluin) on Thursday, May 08, 2003 - 06:23 pm: Edit

I took it this morning. I didn't think it was too bad at all. The MC was easy, the FR moderate as you guys have said. I pretty sure I got my five.

 By Cooljay687 (Cooljay687) on Thursday, May 08, 2003 - 06:54 pm: Edit

I omitted around 10-15 multiple choice. Am I doing bad?? Those that say the mc was "easy," how may did you omit?

 By Quarky (Quarky) on Thursday, May 08, 2003 - 06:56 pm: Edit

It was relatively easy. I am sure I got around 35 questions right. I omitted 2 questions.

 By Cooljay687 (Cooljay687) on Thursday, May 08, 2003 - 07:00 pm: Edit

Argh Im so mad. In my room, I noticed some people were cheating which ticked me off. Please tell me we all had different versions of the test perhaps the answers mixed up to prevent cheating? Something tells me we had had same test.. which would mean how stupid is that!! They need each row to have different forms to prevent cheating

 By Silentopen (Silentopen) on Thursday, May 08, 2003 - 08:16 pm: Edit

I think I got a 5...

I omitted 7 on the MC... guessed on 2 (with narrowed down to 2 answers) and answered all the others correct (to my knowledge)...

This is around 41.1 if some stupid errors are included. In 1998, the cutoff for 5 was 65 out of 108. So I figure, with minor errors on the FR, I got 4 8.5's, and 4 and 3. This is 82.1... I think I got a five. But, who knows, I probably made some really stupid mistakes and will end up with a 4 .

Wish me luck on AP US tomorrow (Good God!!!).

silentOpen
----------
With the silent... and the open... and the... yeah.

 By Rsk (Rsk) on Friday, May 09, 2003 - 12:16 am: Edit

MC wasn't that bad. i guessed two questions;however, what the heck is free response? most people just sat there and do nothing for the rest of the 30 mins.
hopefully i will got 5, so i wont do again next year

 By Stupid_Guy (Stupid_Guy) on Friday, May 09, 2003 - 03:11 pm: Edit

The BC exam was soooo easy. I made a 5 any day

 By Qwerasdf (Qwerasdf) on Friday, May 09, 2003 - 04:38 pm: Edit

Dude, a 65/108 gets you a 5, which means you can get ~10 wrong, and skip like 2 FRs?

 By Chobo (Chobo) on Friday, May 09, 2003 - 05:49 pm: Edit

The exam was definitely very easy.

Free response were also easy.

The polar one was simple. u rewrote the two equations in polar and integrate.

The McClaurin series was simply sin(x)/x....

 By Gabypa (Gabypa) on Friday, May 09, 2003 - 11:46 pm: Edit

Hello! Mmm-- I came here cuz up there in the PR board no one is listening to me, or editors are just randomly deleting all AP related threads....

poor me, i dunno - im worried and cant concentrate cuz of this, so plz help me!

Anyway, i wanted to ask a favor to some BC genius....Or any BCer willing to help... For those that thought it was easy - plz help!

So, I was wondering if someone would be willing to take a look at my answers for the BC FRQ problems (by e-mail or something, so that editors here won't get pissed) and tell me more or less what i got right or wrong. Problems are going to be included in the AP Central site tomorrow, so I mean, I would do them and send them to you asap, or something like that.

It might sound stupid, but after some threads yesterday i got all confused and worried and... you know. I know i did OK in MC. FRQ make me worry. So...would that be possible? PLEASEEEEEEEEEE?

My email is gabypa@brturbo.com.br

 By Eurostar (Eurostar) on Saturday, May 10, 2003 - 01:00 am: Edit

In the second set of free-response, the first problem:
Part B just asked for the tangent line at a point, correct? So, all we had to do is look at the graph of f' and find that, and plug it into the point-slope formula...Or did i totally read that question wrong...sorry, people are freaking me out talking about equations with circles and things.

 By Heatwave345 (Heatwave345) on Saturday, May 10, 2003 - 09:06 am: Edit

i'm not a BC genius, but i'll be willing to look at your work and see if it matches mine.

my e-mail is heatwave345@hotmail.com

BTW. do you have a link to the questions at AP Centra?

 By Gabypa (Gabypa) on Saturday, May 10, 2003 - 09:37 am: Edit

Hey, Heatwave!

Thanks! I will be sending them to you as soon as I have them - I dunno why, but the collegeboard ppl are taking long to put them up, apparently.... GRRR But as soon as they post the thingies, I'll do them and send that e-mail to you. :-)

Thanks once again. Here's the link:

http://apcentral.collegeboard.com/members/article/1,3046,152-171-0-8031,00.html#name5

 By Gabypa (Gabypa) on Monday, May 12, 2003 - 06:02 pm: Edit

they are out now

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