sec^2x / csc^2x
sec(x) = 1 / cos(x) ---> sec2(x) = 1 / cos2(x)
csc(x) = 1 / sin(x) ---> csc2(x) = 1 / sin2(x) ---> 1 / csc2(x) = sin2(x)
sec2(x) / csc2(x) = sin2(x) / cos2(x) = tan2(x)