The concavity test determines where a function is concave up or concave down by analyzing the sign of its second derivative. If $f''(x) > 0$, the function is concave up at that point, and if $f''(x) < 0$, it is concave down.
Second Derivative: The derivative of the first derivative, used to analyze the concavity and inflection points of a function.
Point of Inflection: A point where a function changes its concavity, indicated by a change in sign of the second derivative.
First Derivative Test: A method used to find local maxima and minima by analyzing the sign changes in the first derivative.