Official 2010 Calculus AB/BC FRQs Discussion

<p>Man, 2b even tells you to explain the meaning of the average value “in terms of the number of entries.” How did I manage to get “average number of hundred of entries per hour?”</p>

<p>Oh ****. For question 2, the trapezoidal approximation, I accidentally read the first row as E(t) and the second as t. Got 98.5/8 = 12.313. -___-;;;</p>

<p>So, how many points off do you guys think that is? Lol…</p>

<p>And I took 98.5 from the integral (0,8) E(t) trapezoidal approximation and subtracted it by integral (8,12) E(t)dt in part c, too. Ughhh…</p>

<p>^ Usually, questions like the trapezoidal approximations as featured this year are worth 3 points: 1 for doing a trapezoidal computation, 1 for getting the correct value of 1/8*integral(E(t)) dt, and 1 for the interpretation. The interpretation point doesn’t depend on the value of the integral at all. You might even get a point for doing what they deem to be a sufficiently interesting trapezoidal approximation, although I’m less certain of that.</p>

<p>As for part (c), they’re supposed to follow your work in general. If you misinterpreted E(t) to be the rate at which votes are being cast – and explicitly made that mistake in part (b) during the explanation piece – there’s a chance that they’ll then your answer in part (c) as the correct follow-up with the same incorrect interpretation you’ve given previously. Is this one of those cases where they’ll follow? My gut tells me no, but I certainly think there’s a chance…</p>

<p>I said “4 hundreds of entries per hour” for part a and “7 hundreds of entries” for part c
They won’t count of because I didn’t put “400 entries per hour” and “700 entries” will they?
They asked for the answer in hundreds of entries for part a so that’s why I just put the number followed by “hundreds of entries.”</p>

<p>UVAhopeful that should be fine, it’s still the same number.</p>

<p>For the trapezoidal one, the first trapezoid was a triangle right? Cause it started at (0,0) so there was only one base.</p>

<p>For trapezoidal, I had absolutely no idea had to do it when the steps were not equal. I used the formula h/2 * (y(n)+2y(n+1)+2y(n+2)+…y(last term)) and the divided by 8. h=2 because that’s how big the step is when you cut 8 into 4 pieces. I got 12.375 as my answer. I know my definition is correct but I doubt my computation was correct.</p>

<p>^^ Yes, the first trapezoid was a triangle.</p>

<p>^ When the trapezoids aren’t of equal step sizes, you need to calculate the area of each trapezoid individually. That’s one of the reasons why I never use the Trapezoidal “Rule”, since the AP exam rarely tests the concept that way.</p>

<p>I just make a sketch of a curve through the data points and draw trapezoids. Then I use ((b1+b2)/2)*h to find the areas and then I add them up. It’s failproof, in my opinion.</p>

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<p>Same lol, that’s what I did. I probably didn’t even notice whetheri t was a triangle or not lol.</p>

<p>Does anyone know when will the OFFICIAL College Board AP solutions guide come out?</p>

<p>What’s the maximum point deduction for too many terms in BC Question 6 parts c and d?</p>

<p>Trapaziodal sum: </p>

<p>((h1+h2)/2)(BASE)</p>

<p>For the question where you had to write a piece-wise function (Calc AB form A), is it ok if the piece-wise function included integrals? Or did each piece have to be an antiderivative…</p>

<p>So was the answer to Trapezoidal one 10.something?</p>

<p>^It’s still stored in my calc, it’s like 10.816.</p>

<p>The piecewise function didn’t need integrals or antiderivatives.</p>

<p>

10.865? Or 10.685? I vaguely remember some combination of those numbers.</p>

<p>Does anyone know when will the OFFICIAL College Board AP solutions guide come out? </p>

<p>^
I want to know this too.</p>

<p>Not for a while.</p>

<p>Ok cool because that is what I got but it seemed like a very strange answer…and having to find the average value in addition to the TRAP sum was throwing me off.</p>

<p>And for 2d, would they give any points if you said 9.184 and explained your reasoning that the function increased to the left and decreased to the right and was therefore a max? I realize now that the answer is 12, but I made the chart and everything lol.</p>