Consider the points $P(1,1,4)$ and $Q(5,3,6).$

a$.$ Find vec$(PQ)$ and state your answer in two forms: $($:$a,b,c$:$)$ and $ai+bj+ck.$

b$.$ Find the magnitude of vec$(PQ).$

c$.$ Find two unit vectors parallel to vec$(PQ).$

a$.$ Find vec$(PQ).$

vec$(PQ)=,i,i+1,j+,|k||$