The general solutions for the harmonic oscillator differential equation fall into four general categories: 1) Undamped: [math]x(t) = Ae^{i\omega t}[/math] This is a free-running sinusoidal oscillation that doesn't change over time.
Key Facts. 1  Itâs normal to have mild cramps during your period. 2  Menstrual cramps often start 1-2 days after your period begins. 3  If your cramps donât get better with over-the-counter medicine, you should see your health care provider.
Some women have cramping days before, some have it only after they start their period. Know your body and how it normally responds to you monthly. If it does not feel like your menstrual cycle and you have had unprotected sex, pay attention not only to the heaviness of spotting, but also to its duration.