datatable.math.arccos()¶
Inverse trigonometric cosine of x.
In mathematics, this may be written as \(\arccos x\) or \(\cos^{-1}x\).
The returned value is in the interval \([0, \frac12\tau]\),
and NA for the values of x that lie outside the interval
[-1, 1]. This function is the inverse of
cos() in the sense that
cos(arccos(x)) == x for all x in the interval [-1, 1].