Using the graphs of f and f", indicate where f is concave up and concave down. Give your answer in the form of an interval.
NOTE: When using interval notation in WeBWorK, remember that:
You use 'INF' for ∞ and '-INF' for -∞.
And use 'U' for the union symbol.
Enter DNE if an answer does not exist.
f is concave up on
f is concave down on