vader1990

On a scale of 1-10, 5 being AP LEVEL; 1 being HALF OF AP DIFFICULTY, and 10 being DOUBLE AP DIFFICULTY.

Where on the scale do these 2 books fall with respect to their practice AP tests, and the actual AP Calculus BC Test!!

Thanks

blue_sky

I'd like to know too

diamondbacker

I'd like to know too...

Some of the Barron's questions are just plain tough and unlike what I saw in others.

vader1990

Good Review Question:
The base of a solid is the region bounded by the parabola x^2 = 8y, and the like y=4, and each cross-section perpendicular to the y-axis is an equilateral triangle. What is the volume of this solid?

DISGUISED BUMP

diamondbacker

Is it 128*sqrt 3?

meh, I hate these kinds of problems...

ANOTHER DISGUISED BUMP

vader1990

^NO, its not 128*sqrt 3, but close...

make sure you remember that its perpendicular about the y-axis, and that the cross-section is an equilateral triangle?

If you cannot figure it out just post here, and I'll post a detailed solution back ASAP

ANOTHER DISGUISED BUMP++

EDIT: ok, to save time here's the solution:
ok, so it says that x^2 = 8y, and y=4, and the area is a triangle equilateral

The area of an equilateral-triangle is side^2 * sqrt(3) / 4..and the side will equal the length of the bounded region (the length of the rectangular sub-interval)...

Now since it says that its about the y-axis I find it easier to convert y in terms of x; so x = +- sqrt(8y), between 0 and 4 (4 because y=4 is now x=4)...

so sqrt(3) / 4 INTEGRATION[from 0 to 4] of (2*sqrt(8y))^2 dy (I said 2 times the square root, because the function is plus and minus[above and below the x-axis] and they are both equal in are so, the length of the box will be the sum of both the areas so 2 *) will yield: 64 * sqrt(3)

diamondbacker

Ah I got it... I was doing it right, but I just made a stupid algebra mistake.

Yet I seem to have used a different method.

I graphed it and saw, again, that it was symmetric around the y-axis. I said that the cross-sectional area was (1/2)(sqrt(8y))(sqrt(8y)*sqrt(3))

(Because x^2 = 8y, and x = sqrt(8y), and the side ratios for the equilateral triangle)

I integrated the area from y=0 to y=4 and got 64*sqrt(3)

DISGUISED BUMP +++

vader1990

^yeah i personally hate these type of questions too...this one is from barrons, and I think is a notch above AP...or maybe it isn't, making such a judgment is what my original topic was about anyway...lol....none-the-less goojob at getting it right

anyone know the answer to my topic's title????????

diamondbacker

^ ditto. I've been trying to use Barron's today and when I use it feel stupid, but I'm not doing a bad on the practice AP exams I have... so that's why WE NEED AN ANSWER TO THE THREAD'S QUESTION!

please???????????????????????????

Yatta!

From my personal experience:

Barron's: 8/9
Princeton Review: 4/5

I took the BC exam last year and got a 5.

The Barron's book was overall harder than the real test. The questions in the Barron's book were much more tedious and the concepts they tested you on were a bit tougher than the actual test. If you want to be over prepared for the AP exam, use Barron's.

The Princeton Review Book was around the same difficulty as the actual test. I found the multiple choice questions to be the same difficulty and the FRQ a bit easier than the actual test.

As for the BC test it self, the multiple choice was a complete joke. There is nothing tedious in either of the two sections and if you were half-paying attention in class, you should do well on this section. The FRQ I thought was more of a challenge as the concepts were a bit trickier, but not too tough.

Sixthsense

does anyone know how petersons compares with relation to the ap exam.

THANKS!

Sixthsense

wow...sorry my computer froze and ya... but does anyone know the answer to my question