Cofunction identities are properties like this for two complementary angles ##alpha## & ##beta##:
##sinalpha = cosbeta##
##secalpha = cscbeta##
##tanalpha = cotbeta##
##cosalpha = sinbeta##
##cscalpha = secbeta##
##cotalpha = tanbeta##
The co stands for complementary. The cofunction for a function has the prefix co in front of the function name. For example sine & cosine are cofunctions.
The reflection properties have to do with angles going in the opposite direction.
##sin (-x) = -sin x##
##cos(-x) = cos x##
##tan(-x) = – tan x##
##csc (-x) = – csc x##
##sec (-x) = sec x##
##cot (-x) = -cot(x)##
