question_answer

All trigonometric functions are periodic, but only sine or cosine functions are used to define S.H.M. Why?       

Answer:

                All trigonometric functions are periodic. The sine and cosine functions can take value between ? 1 and + 1 only. So they can be used to represent a bounded motion like S.H.M. But the functions such as tangent, cotangent, secant and cosecant can take value between 0 and \[\infty \] (both positive and negative). So those functions cannot be used to represent bounded motion like S.H.M.