Question

if and g are differentiable at x then so is their product (f.g)'(x)=f(x)g'(x)+g(x)f'(x) plz give the answer

Answer 1

That is telling you one of the rules of differentiation. If I am reading it correctly. It states that the derivative of two products is simply the derivative of the first times the second plus the first times the derivative of the second. I hope this helps.