numpy.arcsin¶

numpy.
arcsin
(x[, out]) = <ufunc 'arcsin'>¶ Inverse sine, elementwise.
Parameters: x : array_like
ycoordinate on the unit circle.
out : ndarray, optional
Array of the same shape as x, in which to store the results. See
doc.ufuncs
(Section “Output arguments”) for more details.Returns: angle : ndarray
The inverse sine of each element in x, in radians and in the closed interval
[pi/2, pi/2]
. If x is a scalar, a scalar is returned, otherwise an array.Notes
arcsin
is a multivalued function: for each x there are infinitely many numbers z such that sin(z) = x. The convention is to return the angle z whose real part lies in [pi/2, pi/2].For realvalued input data types, arcsin always returns real output. For each value that cannot be expressed as a real number or infinity, it yields
nan
and sets the invalid floating point error flag.For complexvalued input,
arcsin
is a complex analytic function that has, by convention, the branch cuts [inf, 1] and [1, inf] and is continuous from above on the former and from below on the latter.The inverse sine is also known as asin or sin^{1}.
References
Abramowitz, M. and Stegun, I. A., Handbook of Mathematical Functions, 10th printing, New York: Dover, 1964, pp. 79ff. http://www.math.sfu.ca/~cbm/aands/
Examples
>>> np.arcsin(1) # pi/2 1.5707963267948966 >>> np.arcsin(1) # pi/2 1.5707963267948966 >>> np.arcsin(0) 0.0