laserbase

^^i overthought that question and i only put 4-6 i thought the slope had to be curving towards x=1 ...urghhh nvm...

Freezenthaw

if you write it like that is it ok?

assuming you've explained yourself correctly

TheMathProf

If it were really clear that you were describing the interval from 0 to 1, and not doing some kind of 0 minus 1 subtraction, then I would imagine you'd probably be fine in most cases. The only times that I can imagine that you'd still run into trouble in those cases is when one of the endpoints is excluded. At least when I hear, from 0 to 1, I assume you're including the endpoints, so if the correct answer were (0,1), I'd guess you'd lose the point.

Freezenthaw

right...but none of the problems above had any excluded end points so I guess I got lucky.

Thanks MathProf appreciate it

blah1290

Two questions
For that one with (0,1) and (4,6) are you sure its not [0,1)U(4,6] because i dont see how the endpoints wont be included. Also does this matter? It would seem to me this is a pretty trivial difference...and its a matter of definitions.

Also what if you set up a negative integral? For example I got 1a, 1b, and 1c right but all of them i got negative answers (-4 and stuff) so i just tacked on a negative sign before the integral to get the positive answer. is that a big deal (because its easy to see that you can distribute the negative sign into the integral)

for me, i think i got 6/9/9/7/9/4 or something...sucks yea i knew i did 6c wrong when my anwer was greater than 8 but i kept it...

paulmjk2

i put 972 because it's asking for number of ticket.. and if ~972.7 tickets were sold, the number of tickets that were sold did not actually reach 973, and that's why i just left it as 972. Do you guys think ill get point off on that?

snipez90

It told you to round to the nearest whole number so you're going to get a point off for not following directions. No big deal though.

blah1290

So is it okay if you put a negative integral? Becuase it got me the same answer...and its easy to see that you can distribute the negative sign into the integral to get the right one (or just switch the two things around), but i didnt have time...

and do they count of for includion/exclusion on endpoints?

that seems too picky, kinda like in comp sci they dont count off if you are missing things like semicolons and stuff.

and can someone explain why the speed is decreasing? cause the graph from 2,3 is moving to the right and up so dy/dt and dx/dt are both increasing, which would increase the speed?

Freezenthaw

speed decreases cause its the magnitude of velocity and velocity is getting closer to 0. Thus the value of velociy must be decreasing.

for part 1d. My calc teacher did it today and got an even '8'. He said something about average value of surface area. Does anyone know what this meant??? I got it wrong anyway but just curious.

blah1290

oh crap!!! i think i got like 24,25,or 26.something-cant remember somewhere aroudn there i was rushing at the end of the calc section., which explains it because i multiplied by pi crap...i hope they still give me some credit because technically my integral was correct, if you dont count the pi....attatched to it.

Freezenthaw

yeah you'll probably get minus one for the answer but everything else will be ok. I'm sure you did fine...and better than i did haha

theworld8905

Hey everybody. I didn't read the whole thread, but I just felt that since I took the BC exam last year, that I maybe should calm a few nerves as to the grading. I made a few mistakes on last years BC exam and still got a 5. The curve is crazy. If you did alright on the multiple choice, and got most of the free response, you should get a 5. I don't remember exactly, but on last years exam I messed up when I took the derivative of the Taylor polynomial for one of the free response questions. I don't remember if that messed up the rest of the question, but remember that you do get partial credit.

TheMathProf

On question 4d, they'll usually accept it either including or excluding the endpoints. Technically, the answer should be [0, 1] U [4, 6]. By definition, a function is decreasing on an interval [a, b] if for any two points x1 and x2 where x1 < x2, f(x1) > f(x2). This is true even including the endpoints: v(1) < v(0.9) < v(0.8), etc.

The problem is that folks start saying that a function g is decreasing whenever g'<0, when it really should read that whenever g'<0, g is decreasing. Slightly different in meaning.

As far as the integral situation, I think you'll technically be fine by sticking the negative out in front.

As far as 1d, the answer that I had was integral (0, 2) of (sin (pi*x) - (x^3 - 4x))(3-x) dx = 8.36995. I'm not sure why you would need the average value of surface area...

Freezenthaw

how many of your part II Frq points do you think you received^^

thankss

blah1290

yea thanks, i should stop worrying.
i worry about every test i take-usually about bubbling in also (for some reason on the AMC last year i thought i misbubbled every answer so i worried about ti for 2 weeks until the scores came back to show i didnt misbubble anything -and also i usually ask my friends what was the answer to this, do you remember it..and stuff) but i should just remember its done and over with you cant change anything.
oh well i think the curve is awesome, from the AP centrals website, about 45 percent got 5s last year for AP calc when only like 11 percent got 5s for AP euro

oh yea and i think for something like 1a, i wrote a different integral. i noticed that the sin's area above and beneth the curve were the same so i just only used x^3-4x without the sin thing in it, i think that should be okay since i metioned it and i said the areas were the same.

If its 64-108.
for 5

i think you can get 5/5/4/5/5/4=28 and then 33/45 on MC missing 12 questions for 30/45 to get 30*6/5+28=64 still. sweet curve.

why isnt it like this on other AP tests? i the scoring range predetermined or something?