asin acos atan

(asin number) (acos number) (atan number)

The inverse trigonometric functions, each returning an angle in radians as a float. asin is the arcsine, acos the arccosine, and atan the arctangent. Only the one-argument atan is supported -- there is no two-argument (atan y x) form. All three work on every backend: the interpreter and JVM use Math.asin/Math.acos/Math.atan, while the WASM backend computes atan with a software approximation (argument folding plus a Taylor series, ~1e-15 relative error) and derives asin/acos from it, so a WASM result can differ from the interpreter's and the JVM's in the last digit or two. (asin 1) is exactly pi/2, (acos 1) exactly 0.0, and an asin/acos argument outside [-1, 1] returns NaN.