Trigonometric functions

The trigonometric functions SIN, COS and TAN return the value corresponding to their argument in radians. SIN and COS are well-defined, continuous and differentiable for all values of their arguments; care must be exercised when using TAN because it is discontinuous.

The inverse trigonometric functions ARCSIN and ARCCOS are undefined for arguments outside the range -1 to +1 and special care is required to ensure that no attempt is made to evaluate them outside this range. Derivatives for the inverse trigonometric functions are always calculated numerically.