Excellent Quondum and though I think in the redirect a slightly larger discussion of the advantages of using tau would be helpful in understanding why anyone could have thought of a seemingly unorthodox mathematical proposal The redirect already has the advantages of the notation of a turn in terms of tau like a half revolution would be tau 2 but I believe a small discussion on the advantages on the sine function like in this old Vi Hart video would very much strengthen the argument It doesn t have to be large Or maybe that could appear on the sine page