OK, so this calls for a 2nd derivative test. So this is what I did:
That's how far I got with it. The answer is supposed to be the interval
Did I botch something somewhere?
Problem: For what values ofis the curve
concave downward?
OK, so this calls for a 2nd derivative test. So this is what I did:
. That was easy. But now we have a product.
. Now, if I'm looking for concave downward, I want the value of the
expression to be
,
. We know
; then we must be really looking for
That's how far I got with it. The answer is supposed to be the interval.
Did I botch something somewhere?
I did wonder if I'd messed up on the 2nd derivative. Thanks, Martingale!