How to determine the function from its graph if it has a non-simple shape? Given a graph (see attachment) where set of coordinates of any point is known. Are there any techniques to find an equation of the function? So far i can guess, that i need to measure the derivative at multiple points, then plot it, then find graph of second derivative and so on until i get a 0 derivative, and then integrate backwards to obtain original equation. Could anyone please mention whether there are some techniques to perform such evaluations i could read about?