Multiple Choice: Given f(x) =
−4x2 + 7x, then f is concave up for … Homework Help ✎
x ≠ 0
no values of x
x < 0
x < 0 or x >
0 < x <
Recall that candidates for points of inflection occur where the 2nd-derivative equals zero AND where the 2nd-derivative does not exist.
After you identify where f ''(x) = 0 and where f ''(x) = DNE, check the regions before, after and between those candidates: if f ''(x) > 0, then f(x) is concave up.