AP Calculus AB 2013 Thread

<p>Uh oh… I might have screwed up on that whole problem. What was the original equation</p>

<p>I agree with siddg911</p>

<p>that whole question, and the fact that we had to calculate the area without a calculator was a bit of an overkill…</p>

<p>sorry, then it would just be my previous equation with +1. it ends up being zero. -ln(-1). the point was like (1,0) or something like that</p>

<p>What was the original equation for 6?? Might have screwed up on the whole thing…</p>

<p>ln(-1) is not a real number…</p>

<p>guessing, but i think that it was dy/dx=(e^y)(3x^2-6x)</p>

<p>Yeah for the concave down and increasing I said 0<x<1 and 3<x<4 that was it</p>

<p>That was the differential equation.</p>

<p>I think that’s what it was. I got like -.6 for the first part which I kind of guessed on and ln(x^3-3x^2) - ln(2) or something like that for the second part.
Not sure if I did it right… Probably didn’t. I thought the calculator MC was easier than the noncalc MC. I don’t really know how I feel about the FRQs though. Not sure which ones I did right…</p>

<p>I got the same on part a. I butchered part b, I’m almost certain I will only get the separation of variables point.</p>

<p>I got (0,1) for one of the concave down increasing intervals but I was short on time and didn’t even bother finding the other(s).</p>

<p>Did anyone else get 4 for the area of R in the free response?</p>

<p>What did i do wrong?
Dy/dx = e^y(3x^2-6x)
Integral 1/e^y dy = integral 3x^2 -6x dx
Ln|e^y|=x^3-3x^2+c</p>

<p>^ if that was the answer I will cry. Did I ACTUALLY do it right??</p>

<p>Yay did you do that too???</p>

<p>@etisawesomez i was in the same boat, but you can not take ln of 1/e^y. i just looked it up. you have to treat it as e^-y and then integrate.</p>

<p>Because i had 10 minutes to check and felt confident… Might have done something stupid though :(</p>

<p>i think you would have had to make the stuff in the ln abs value so ln( abs (x^3 -3x^2 +1)) so you dont get the ln of a negative number</p>

<p>@siddg911</p>

<p>Youre right. So will i only get 1 point for that whole problem??? This is depressing</p>