by the mass sideways,
Angular frequency of oscillation:
(a) As time is noted from the mean position, hence using
(b) At maximum stretched position, the body is at the extreme right position, with an intial phase of rad. Then,
(c) At maximum compressed position, the body is at left position, with an intial phase of . Then,
The functions neither differ in amplitude nor in frequency. They differ in intial phase.