Inverse trigonometric functions - Wikipedia, the free encyclopedia
(Note: Some authors define the range of arcsecant to be ( 0 ≤ y < π / 2 or π ≤ y < 3 π / 2), because the tangent function is nonnegative on this domain. This makes some computations more consistent. For example using this range, tan(arcsec(x)) = √ x 2-1, ...