For the function

MATHEMATICS · Single correct · AP · Calculus AB · Analytical Applications of Differentiation · Analytical Applications of Differentiation

Problem

For the function

y=\arctan x

, on which of the following intervals is the graph of

y

concave down? (a)

(-\infty,0)

(b)

(0,\infty)

(c)

(-1,0)

(d) The graph is nowhere concave down.