Re: [math-fun] True or False, Log[Tan[t + p/4]]

I like this proof method best of all. But there needs a workaround of the usual proof that the antiderivatives of 2 sec(2x) all differ by just a constant. That does not hold in this case, since each sigmoid of the original function can be slud up or down by an arbitrary amount. —Dan ----- f(x) = log(tan(x + pi/4)) f(0) = 0 and f'(x) = 2 sec(2x) is even, hence f(x) is odd. -----