Sir in this question only one doubt why unit vector direction is negative while in question it say outward

3 x, y,2) E R'. Sr +y+#s1/ and F- +#) lor )eV. Lt denote the outward unit normal vector to the boundary ofV and S denotes the part y,)e R x +y+z' of the boundary of V. Then F-hdS is equal to (a)-8 T Solution: (a) Outward unit normal to boundary of V (b) 4T (c) 4t (d) 87 xi ++ zk 1/2 -2(xri ++ z) +y+.i + ý+ zk)Jds -2y+ JFhds --2+y+zk as -8 ds Since,x++#=on S 4 -8x 47=-8t