# datatable.math.arcsin()¶

Inverse trigonometric sine of x.

In mathematics, this may be written as $$\arcsin x$$ or $$\sin^{-1}x$$.

The returned value is in the interval $$[-\frac14 \tau, \frac14\tau]$$, and NA for the values of x that lie outside the interval [-1, 1]. This function is the inverse of sin() in the sense that sin(arcsin(x)) == x for all x in the interval [-1, 1].