Аннотация:The problem of maximizing the horizontal coordinate of a point mass moving in a vertical plane under the action of gravity forces, viscous friction, support reaction of the curve and the thrust is considered. The penalty for the control expenditures is included in the goal function. Assumed that inequalitytype constraints are imposed on the slope angle of the trajectory. The system of equation belongs to a certain type that allows reduce the optimal control problem with state constraints to the optimal problem with control constraints. As a result, the sequence and the number of the arcs with motion along the phase constraints are determined and the synthesis of the optimal control is designed. It is shown that optimal trajectory of the Brachistochrone problem with viscous friction contains no more than one section of motion along the lower constraint and no more than two sections of motion along the upper one.