I f I can have these solved I would be a happy man.......

two vibrations, x1 = 3sin (10t + pi/6) and x2 = 2 cos (10t - pi/6) where t is in seconds, are superimposed. Determine the time at which the amplitude of the resultant vibration, x1 + x2, first reaches a value of 2.

can anyone solve?? I must be a fool cause I been over it many times and maybe that is the problem!!!!!

please help.