I wish that made any sense at all. Can you learn just enough LaTeX to communicate better? Perhaps the actual text to the problem statement?
if f(x)*f(y)+2=f(x)+f(y)+f(xy) for every x belonging to R and f(1)=f(first differential)(1)=2 then f(2) is equal to
i treated y as constant and differentiated with respect to x
should i follow the basic method of differentiation by using limits