Consider the points $A=(1,1,6)$ and $B=(-1,6,2)$ in $R^3.$

$($a$)(2$ pts$)$ Find the distance between points A and B $.$

$($b$)(2$ pts$)$ Find the distance between the point and yz plane.

$($c$)(4$ pts$)$ Find the vector having initial point A and terminal point $B*vec((AB)).$ Also find the magnitude of this vector as well as unit vector in the direction of vec$(AB).$