A Model of f(R) Gravity as an Alternative for Dark Matter in Spiral
  Galaxies
  In this paper we study consistent solutions of spherically symmetric space in
metric f(R) gravity theory. Here we inversely obtain a generic action from
metric solutions that describe flat rotation curves in spiral galaxies without
dark matter. Then we show that obtained solutions are in conformity with
Tully-Fisher relation and modified Newtonian dynamics, which are two strong
constraints in justification of flat rotation curves in spiral galaxies.
