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.
Menstrual cramps cause pain in your the lower abdomen during the first few days of your menstrual period. Sometimes the pain radiates to lower back or both thighs. Some girls also have nausea, vomiting, diarrhea, or dizziness along with cramps.