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.
In this article. Dysmenorrhea is the medical term for the painful cramps that may occur immediately before or during the menstrual period. There are two types of dysmenorrhea: primary dysmenorrhea and secondary dysmenorrhea. Primary dysmenorrhea is another name for common menstrual cramps. Cramps usually begin one to two years after a woman starts getting her period. Pain usually is felt in the lower abdomen or back. They can be mild to severe. Common menstrual cramps often start shortly before or at the onset of the period and continue one to three days. They usually become less painful as a woman ages and may stop entirely after the woman has her first baby.