I don't believe substituting tau for 2-pi requires redefining either pi or radians. Rather it simply changes what you say you are multiplying by: instead of a c

I don't believe substituting tau for 2-pi requires redefining either pi or radians. Rather it simply changes what you say you are multiplying by: instead of a circle being 2-pi radians, it's tau-radians. These are both saying the same thing, without changing pi or radians.