Please ask about proving Newton Leibniz formula Proof: let the upper limit be a variable, define a new function g [x], prove G '(x) = f (x), and then say g (x) C = f (x), but doesn't g (x) = f (x) C also hold?

Please ask about proving Newton Leibniz formula Proof: let the upper limit be a variable, define a new function g [x], prove G '(x) = f (x), and then say g (x) C = f (x), but doesn't g (x) = f (x) C also hold?

I don't know: G (x) C = f (x), G (x) + C = f (x), or G (x) * C = f (x). I don't think this problem is meaningful. You are confused about calculus. You don't understand the meaning of upper bound function! It's confused with general function