Find the general solution or the general expression for all angles, whose cosine is zero.
To find general value of x when tanx = tany
We have tanx = tany
sinx cosy - cosx siny = 0
sin (x - y) = 0
where
where
Hence, when tanx = tany,
then general value of x is given by
where
COROLLARY: If cotx = coty tanx = tany
So, when cotx = coty, then x = where