Bin for half maximum


I have an enoying problem! I need to find the x-value where my function has fallen to half, i.e. x for y=ymax/2. My function is nice and continous (exponential) and in the form of a histogram (TH1). How can I do this? Is it even possible? I realise that in a general case this could be difficult since you might get several x-values for a given y-value, but not in my case.


see TF1::GetX