I am working on a simulation and need to insert this graph as a current source and of course I can only do this by inserting the graph equation. However I'm not sure on how to obtain the equation of this graph. The graph shown is not symmetrical to each other but I only need the equation of the general shape which means it can be assumed to be symmetrical.
Thank you in advance.
On
My best fit:
$$f(x)=a\cdot\sin^7(bx)$$
where you have to adjust $a$ and $b$, so that it fits your scaling. The picture was generated with $a=3.444,b=1$, but this is special to the used axes scaling and has to be adjusted for your exact application.
To the question in your title
No. There is not an explicite formula for every possible function graph (in a strict set theoretic sense). But we can aproximate almost surely any function appearing in applciations to any desired accuracy if we want to.
Equations of the form $f(x) = \dfrac{\sin^a(bx)}c$ seem to be a good approximation for your given curve.
For example ,
with $a =23,b=40,c=10$
NOTE : for your curve $a$ should always be odd . $b$ and $c$ are just scaling factors , $c$ can also be kept constant as it keeps the graph bounded between $y= [0.1,-01]$