Asin (arcsine)

Syntax

Asin(<number>)

π Asin(ratio) → angle_rad (Triangles)

Description

Asin returns the arcsine: the angle, in radians, whose sine is the input. It is the inverse of Sin, used to recover an angle from the ratio of two sides.

Technical Description

Asin(x: NUMBER) → NUMBER. Returns asin(x) in radians, in [−π/2, π/2] (Math.asin). The argument must lie in [−1, 1], else an evaluation error, as PostgreSQL raises. NULL input returns NULL. PURE, DETERMINISTIC. Floating-point result. SQL's ASIN(x).

Examples

Angle of incline from the rise and the length of the slope:

π Degrees(Asin(rise / length)) → incline_deg (Ramps)

PROJECT Degrees(Asin(rise / length)) -> incline_deg (Ramps)

Limitations

Errors on an argument outside [−1, 1]. Returns radians. NUMBER only; NULL in → NULL out.

Alternatives

Acos and Atan2 recover an angle from other ratios.

See Also

sin, acos, atan2, degrees