48 hours have passed! AP Calc AB FRQ Discussion

<p>I’ll take a stab at the points:</p>

<p>1.(a) 2 points: 1 - answer, 1 - units
(b) 2 points: 1 - interpretation of the integral, 1 - value of the integral
(c) 2 points: 1 - turning around at t = 2, 1 - justification
(d) 3 points: 1 - calculating Caren’s distance from school, 1 - calculating Larry’s distance from school, 1 - comparison of who lives closer</p>

<p>NOTE: Part (d) seems like it’s worth too many points (the comparison isn’t really calculus), but I’m not sure what other part could receive a third point instead.</p>

<p>2.(a) 2 points: 1 - integral, 1 - numerical solution
(b) 3 points: 1 - sets R’(t) = 0, 1 - finds the t-value, 1 - justifies an absolute maximum
(c) 2 points: 1 - connects w(2) - w(1) to integral(w’(t), t, 1, 2), 1 - numerical solution
(d) 2 points: 1 - integral, 1 - numerical solution</p>

<p>NOTE: I’ve sometimes seen problems like this before where the constant in front of the integral in part (d), in this case 1/(solution in part (a)) is part of the numerical solution point and not the integrand point.</p>

<p>3.(a) 2 points: 1 - calculates the cost to produce with an integral, 1 - profit
(b) 1 point - proper explanation that includes units
(c) 2 points: 1 - integral expression, 1 - rest of equation
(d) 4 points: 1 - finds P’, 1 - solves P’ = 0, 1 - evaluates P’ at student’s local max, 1 - justification (0/4 for any process to find P’ that doesn’t work with an integral expression)</p>

<p>4.(a) 3 points: 1 - limits, 1 - integrand, 1 - solution
(b) 3 points: 1 - integral, 1 - antiderivative of A(x), 1 - solution
(c) 3 points: 1 - limits, 2 - integrand as a function of y</p>

<p>NOTE: I’m not confident in the points for part (b) of this. Is it possible there’s another point elsewhere? I doubt they’ll regive the limits point for recycling the limits from part (a), but maybe?</p>

<p>5.(a) 2 points: 1 - difference quotient, 1 - solution
(b) 1 point: solution supported by student work
(c) 2 points: 1 - left Riemann sum set-up, 1 - solution
(d) 4 points: 1 - finds tangent line, 1 - finds secant line, 1 - evaluates tangent and secant lines at x = 7, 1 - uses concavity to justify inequalities</p>

<p>NOTE: Part of me wants to give part (b) 2 points and I’m not exactly sure what you could show as a 1 point answer. If it has 2 points, we probably remove a point from part (d), probably the third of those four points. I think there’s also a chance that the justification itself actually is two of the points for part (d), but it seems doubtful if all they want is a mention of the concavity. Maybe they want a better connection than that?</p>

<p>6.(a) 3 points: 1 - f "(x), 1 - identifies inflection points at x = 0 and x = 2, 1 - justification
(b) 4 points: 2 - f(-4), 2 - f(4)
(c) 2 points: 1 - x-value, 1 - justification</p>

<p>NOTE: I want to say that the points in (b) are broken down as 1 - calculates integral(f '(x), x, -4, 0), 1 - calculates integral(f '(x), x, 0, 4), 1 - antiderivative of f '(x) on [0, 4], 1 - uses initial condition of f(0) = 5 properly. Not sure what they’ll do there exactly. Pretty confident in the overall part breakdowns for this one.</p>

<p>Nitpick away and offer suggestions/alternatives!</p>

<p>Thanks TheMathProf. You make me feel that I have a 5 right now.</p>

<p>can anyone tell me whats the rough composite score out of 108 needed for a 5?</p>

<p>Mathprof,</p>

<p>I have almost identical point awarding as you.</p>

<p>We only differ on question 5 and question 6.</p>

<p>For question 5:
I have part b as being worth 2 points (one for antiderivative of 3x-5f(x). I then assigned one fewer point in part d. </p>

<p>For question 6:
I have part a worth only two (one for points of inflection at 0 and -2 and one for justification).
I had another point in part c for considering the end points in determining where the abs max occurs.</p>

<p>are there different curves for the different papers?
i think i took a different paper… =s</p>

<p>CalculusGuy, I think you may very well be right for #5.</p>

<p>But I think the justification point and sign analysis of f ’ on the interval [-4, 3ln(5/3)] and [3ln(5/3), 4] should be enough for question #6. I did come up with f(3ln(5/3)) being equal to 11 - 9ln(5/3), but I’m not sure that students would be expected to be able to compare the values of 11 - 9ln(5/3) and 8 - 15e^(-4/3) without a calculator.</p>

<p>I’m also thinking that there may be a scoring rubric somewhat similar to 1998 AB2 ( <a href=“Supporting Students from Day One to Exam Day – AP Central | College Board”>Supporting Students from Day One to Exam Day – AP Central | College Board; ) (with the exception of point #2 for that part, since the absolute maximum value of f isn’t asked for in 2009 AB6 for a case such as this one.</p>

<p>Ok so I guess I did allright then. I think I pulled off at least 4’s for all the FRQ’s. Hopefully I did well on the Multiple choice.</p>

<p>Does anyone remember what the actual problem was for #6 (a)? I can’t remember and I am trying to calculate an estimate of my score…</p>

<p>I have a feeling the curve will be below 70…at least I hope</p>

<p>I doubt there will be a generous curve. The FRQ’s were tricky, but MC was a piece of cake.</p>

<p>ahh the curve needs to be generous. I think I’ll get anywhere from a 50-60 and all I need is a 4 for credit…I’ll be so ticked if I need over 60 for a 4.</p>

<p>I think I may have made a hugggggggggggggge mistake… I may have put my answers for some of the FRQ in the wrong number spots, I keep rethinking the order that I did them in, and I may have done that… would they realize what I have done, or am I screwed???</p>

<p>I did the questions out of order, and really didnt pay attention to the number that I was writing down my answers… I may have put question 3 in the question 1 spot, and the question 2 in the question three spot and question one in the question two spot, Im pretty sure I didnt mix up the second section. But, now that I think back, im not sure… ugh</p>

<p>has no one in this topic done form B?</p>

<p>no. its 6 rt(meters) PER METER.
that means 120(25) - 25meters (6)(5).</p>

<p>i ended up getting 2250. some people say 2500, but I don’t think its 2970</p>

<p>i didn’t read through this whole thing but this is to stuff on the first 2 pages</p>

<p>you guys, int(120-6sqrtx,x,0,2) IS THE SAME THING as 120k - int(6sqrtx,x,0,2)</p>

<p>think about it… the integral of 120 is 120x, plug k in and you get 120k.</p>

<p>From this curve I know I got 31 for sure, but not sure if they will give me more points for some doubtful questions. Hoping that I did good on the multiple choice like my final, I hope I can pull off a 5.</p>

<p>ThePerson: I thought the MC was pretty easy as well. Hopefully it’s enough to bring me up</p>

<p>^agreed. It’s all about the MC. I thought the non calc was a breeze and the calculator MC was not bad at all so I think that will really help.</p>

<p>so any1 have an approximation of the curve?
any educated guesses?
howabout the last couple years’ curves</p>

<p>In a different thread, TheMathProf estimates that the curve will be around 70 for a 5. in 2003, the curve for a 5 was 66, which was considered generous by many.</p>