Help! Force of a Spring for "Small" displacements 1. The problem statement, all variables and given/known data Okay, here is the diagram, For "small horizontal displacements" of the mass: For the force exerted by each spring (TOTAL, not resolved) they are using: Fsp=kxcos(45) and then resolving it onto the x-axis they use Fsp x=kxcos25*cos45 I do not understanding this at all. Why is the unresolved force using cos*45 ? I am thinking it has to do with the fact that we are assuming that we are making only "small horizontal displacements" of the mass.