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[apcalculus] onesided derivatives
Posted:
Oct 26, 2012 11:44 AM


NOTE: This apcalculus EDG will be closing in the next few weeks. Please sign up for the new AP Calculus Teacher Community Forum at https://apcommunity.collegeboard.org/gettingstarted and post messages there.  I'm curious how common is it for your students to make the following mistake:
suppose g(x) is defined in 2 pieces, and is not continuous at the break, such as x+1 for x>2 x3 for x<=2
when asked to evaluate g' from each side at 2, the student uses the value of the PIECE for g(2), namely g(2) = 1 from the left, but g(2) magically becomes 3 from the right.
I'm wondering if this is just one of those developmental things where the brain does a reset of prior knowledge, or if my precalc curriculum is unusually weak in this regard.
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