J(A) Un A F 40. Prove that J E AOL mulate and a precise statement of the following: Suppose g E R(a) on [a, b]. Then modifying the value of g at a point where o is continuous, does not change the Riemann-Stieltjes integrability (with respect to alpha a) of (the modified) g". (5) If f(x) - for all mrational x and J(x) = 1 for all rational x show that f & R on [a, b] for any a