The function $f$ is graphed below. State the values that fulfill the following requirements. If there are no such values, type DNE. If there are multiple discrete values, separate them with commas. If there are a whole interval of values that fulfill the requirement, use interval notation to give all of the values in the interval. Type oo for $$ and$-$oo for $-.$ Also type $U$ for $.$ Where is $f^{\text{'}}$ undefined? at $x=$ What are the critical values of $f?$ at $x=$ Where does $f$ have local minimums? at