A vector field is specified as G=24xyax +12(x^2+2)ay+18z^2az.Given two points ,P(1,2,-1) and Q(-2,1,3),find :(a) G at P ;(b) a unit vector in the direction of G at Q ;(c)a unit vector directed from Q toqard P;(d) the equation of the surface on which l Gl =60.