Hi! This is my first ever post on PF. Thanks in advance for anyone who helps me out on this! I'm trying to find a general function that describes the curve in the attached image. As you can see, it is periodic and decays as it approaches infinity. y ≥ 0 at all times; f(0)=0; symmetric about y axis. The period should increase as well - the distance between the first local maxima on the each side of the y axis should be very small (nearly 0) but increases at a very large rate. For example, set the highest local maximas as p and p' and the second highest as q and q'. Well the distance between p and p' <<<< than the distance between p and q (similarly p' and q'). I'll post more drawings if need be. Thank you very much to whoever helps me out with this.