$28$

$23-40.$ Analyzing critical points Find the critical points $of$ the follow$-$

ing functions. Use the Second Derivative Test $to$ determine $(if$ possible$)$

whether each critical point corresponds $to$ a local maximum, a local

minimum, $or$ a saddle point. $If$ the Second Derivative Test $is$ inconclu$-$

sive, determine the behavior $of$ the function $at$ the critical points.

$f(x,v)=(4x-1{)}^2+(2v+4{)}^2+1$