(a) \( \boxed{0} \)
(b) \( \boxed{\frac{7}{50}} \)
(c) \( \boxed{-\frac{7}{50}} \)
(d) \( \boxed{\frac{-x}{x^2 + 1}} \)
(e) \( \boxed{-\frac{x}{x^2 + 1}} \)
(f) \( \boxed{\frac{x + 5}{(x + 5)^2 + 1}} \)
(g) \( \boxed{\frac{3x}{(3x)^2 + 1}} \)
(h) \( \boxed{\frac{x + h}{(x + h)^2 + 1}} \)