AP Calc BC Discussion

TheMathProf
Sat, 12 May 2007 00:04:18 +0000

To Yatta!, re: answer rounded to 4 places causes inaccurate rounding to 3 places:

I don’t think it will work, but it’s worth a try. I know there’s a precedent for accepting an alternative answer that is not accurate to three decimal places.

Basically, the issue came up with the calculation of an integral. On one of the questions, calculating the integral using fnInt on the home screen provided a different answer than using the integration feature within [2nd][TRACE].

Truthfully, the calculator integration feature on the TI-83/84 doesn’t integrate at all, it merely does a Riemann approximation with different numbers of rectangles. fnInt uses 100,000 (if I recall correctly) per unit of x, while the other feature uses fewer (I want to say it’s only 1,000 per unit of x). Once the College Board figured out where the inaccurate answer came from, they accepted both, although I’ve been told at a workshop that this isn’t necessarily a binding precedent.

It’s worth a shot, though. :)