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.
More detail and supporting information is in the main article. 1  Menstrual cramps are pains felt in the lower abdomen, occurring both before and during a woman's menstrual period. 2  The pain can be slight or sometimes extremely severe. 3  There are two types of painful periods-primary and secondary dysmenorrhea.