2. (10 points) A mass on a spring moves symmetrically about x-0 cm as follows: (i) at = Os the mass is at x = 2.5 cm and (ii) it is moving in the positive direction, (iii) At x = 5 cm it turns-around. (iv) At 1-2s it has returned to x = 0 (for the first time since t-0). First, a caution: don't believe everything your calculator tells you! For example, if you calculate cos' (0.921), your calculator will give you 0.4 radians. BUT, also cos(-0.4)-0.921, as well as cos(0.4+2)-0.921, cos(-0.4+2m)-0.921, cos(0.4-2)-0.921, cos(-0.4-2)-0.921, etc. (a) Using (i), (ii), and (iii), find the phase constant o in radians. (b) Obtain an expression for xit). the position at all times.