Creating a function from graph I'm trying to create a function that will generate a graph similar to this awesome paint gif:



This is my attempt thus far: f(x)=-0.0040*(x+200)*(x-200)

I can't figure out how to get my graph to "turn" and go to 0 like in the picture. I've tried different types of absolute values and I guess I could make two separate functions. If it is possible, I really would love to be able to express it in a single function though. Note that the exact values are not that important, I can tweak them later. The shape of the graph is really what I'm looking for (disregarding my artistery with uneven lines).
Two possible guesses. 

Probability Density: $\large y=ce^{-\left(\frac{x-k}{h}\right)^2}$ 

I don't know what a name for this is, but another similar graph is $\displaystyle y=\frac{c}{1+(h(x-k))^2}$.
This looks like an inverse Cosine graph translated vertically by 1 unit. It also looks quite dilated as (x E [-200,200]), therefore its dilation factor should be π/200.
f(x) = cos(π/200 x)+1
Since you didn't mention the y-intercept, I cannot be sure of its amplitude.