Odd functions (negate input, negate output): sin^(-1)(-x) = -sin^(-1)(x), tan^(-1)(-x) = -tan^(-1)(x), csc^(-1)(-x) = -csc^(-1)(x). The "co" functions behave differently: cos^(-1)(-x) = pi - cos^(-1)(x), cot^(-1)(-x) = pi - cot^(-1)(x), sec^(-1)(-x) = pi - sec^(-1)(x). This is because their ranges are [0, pi] not symmetric about 0.