Answer :
f =del F, make the distinction its 2 different functions
in this case its a conservative vec field
u can do Del x F or curl F and see its not 0, but anyway, u can also integrate the portion in i wrt to x and portion in j component wrt to y, and see that even with the constants being functions of the variable not being integrated wrt to, you still cannot find a function g such that f(x,y)=del (g)
in this case its a conservative vec field
u can do Del x F or curl F and see its not 0, but anyway, u can also integrate the portion in i wrt to x and portion in j component wrt to y, and see that even with the constants being functions of the variable not being integrated wrt to, you still cannot find a function g such that f(x,y)=del (g)