Use the given graph of the function $\backslash ($ f $\backslash )$ to answer the following questions. If a question has two or more answers separate them with commas.

$1.$ List the open interval$($s$)$ on which $\backslash ($ f $\backslash )$ is concave upward. For credit your interval$($s$)$ must be as large as possible. Answer $($in help $($intervals$))($use commas rather than U to list multiple intervals$)$:

$2.$ List the open interval$($s$)$ on which $\backslash ($ f $\backslash )$ is concave downward. For credit your interval$($s$)$ must be as large as possible.

Answer $($in help $($intervals$))($use commas rather than U to list multiple intervals$)$:

$3.$ List the points of inflection. List your answers as points in the form $\backslash (($a$,$ b$)\backslash ).$

Answer $($separate by commas$)$: