For each of the following vector fields F, decide whether it is conservative or not by computing curl F. Type in a potential function f (that is, f=F ). Assume the potential function has a value of zero at the origin. If the vector field is not conservative, type N.

A. F(x,y)=(12x+5y)i+(5x+14y)j

f(x,y)=

B. F(x,y)=6yi5xj

f(x,y)=

C. F(x,y,z)=6xi5yj+k

f(x,y,z)=

D. F(x,y)=(6siny)i+(10y6xcosy)j

f(x,y)=

E. F(x,y,z)=6x^2i+5y^2j+7z^2k

f(x,y,z)=

Your answers should be either expressions of x, y and z (e.g. "3xy + 2yz"), or the letter "N"