I have a set (at least 3) of curves (xy-data). For each curve the parameters E and T are constant but different. I'm searching the coefficients a,n and m for the best fit over all curves.

```
y= x/E + (a/n+1)*T^(n+1)*x^m

```

I tried curve\_fit, but I have no idea how to get the parameters E and T into
the function f (see curve\_fit documentation). Furthermore I'm not sure if I understand xdata correctly.
Doc says: An M-length sequence or an (k,M)-shaped array for functions with 
k predictors. What's a predictor?
As ydata has only one dimension I obviously can't feed multiple curves into the routine.

So curve\_fit might be the wrong approach but I don't even know the magic words to search for the right one. I can't be the first one dealing with this problem.