Let the function FX = x + A / x + B (a > b > 0), find the monotone interval of F (x), and prove the increasing of F (x) in its monotone interval Sex

Let the function FX = x + A / x + B (a > b > 0), find the monotone interval of F (x), and prove the increasing of F (x) in its monotone interval Sex

f(x)=(x+b-b+a)/(x+b)
=1+(a-b)/(x+b)
Because A-B > 0, when x > - B or X-B, or X