Hi, Well I would like to know if we can change equation such that the relation between independent and dependent variable will be same but has some different form. Let me explain it: For eg. ψ(t)=-3-43cos(ω*t), is a periodic function. Now when you differentiate it with respect to time the constant term is lost. I would like to know if we can somehow change equation such that the constant term is not lost in differentiation, and also the relationship between ψ and time is preserved.