The first derivative of a function $~g~$ is given by $\qquad g\,^\prime(x)=2(x-0.2)\,$. It is clear that $~0.2~$ is a critical number because $~g\,^\prime(0.2)=0\,$. The value $~g\,^{\prime\prime}(0.2)~$ is [[☃ dropdown 1]], which makes $~g(0.2)~$ [[☃ dropdown 2]].