i have a quick question regarding the unit normal vector on the following integral:

∫∫F•dS = ∫∫F•ndS
s             s

if the surface S is given by z=g(x,y) then the unit normal vector is f(x,y,z)= z - g(x,y)  ⇒

       gradf(x,y,z)
n= -----------------
      |gradf(x,y,z)|

my question is if i'm given the surface 3z=g(x,y), then what should the unit normal vector be???

is it f(x,y,z) = 3z - g(x,y)     or     f(x,y,z) = z - g(x,y)/3

Last edited by Flowers4Carlos (2005-12-20 21:21:43)