text: trigonomery quadratic type equation problem? i have a similar problem to do a project on.  i was wondering how to set it up.  a block is attached to a spring and set in motion on a frictionless plane.  its location on the surface at any time in seconds is given in meters by x= √3 sin 2t+ cos 2t.  for what values of t is the block at its resting position x=0. x=√3 sin 2t+ cos 2t when x=0 so 0=√3 sin 2t+ cos 2t therefore -cos2t=√3 sin 2t so -1=√3 sin 2t/cos 2t and -1/√3=tan2t so 2t=inverse tan (-1/√3) 2t=-30, 150, 330, 510, 690... t=75, 165, 255, 345.... 90a+75 where a is greater than or equal to 0