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.
I get it every time. I usually don't get back pain before or during my period, but some of my friends definitely do. So I'm pretty sure it's totally normal! I think the way to ease period-related back pain is similar to what you'd do to lessen stomach cramps -- use a heating pad, do light exercise, take a bath, etc.