resolve a force of 100 newton into two components which lie on the opposite sides of the force and each of which makes of an angle 30 with t

Well, if you really mean this, then each component would be 100*cos(30°) newtons.  However, you would normally resolve a force into two directions that were perpendicular to each other, in which case one component would be 100*cos(30°) newtons and the other would be 100*sin(30°) newtons.