numpy.arcsin¶

numpy.
arcsin
(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'arcsin'>¶ Inverse sine, elementwise.
 Parameters
 xarray_like
ycoordinate on the unit circle.
 outndarray, None, or tuple of ndarray and None, optional
A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshlyallocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
 wherearray_like, optional
This condition is broadcast over the input. At locations where the condition is True, the out array will be set to the ufunc result. Elsewhere, the out array will retain its original value. Note that if an uninitialized out array is created via the default
out=None
, locations within it where the condition is False will remain uninitialized. **kwargs
For other keywordonly arguments, see the ufunc docs.
 Returns
 anglendarray
The inverse sine of each element in x, in radians and in the closed interval
[pi/2, pi/2]
. This is a scalar if x is a scalar.
Notes
arcsin
is a multivalued function: for each x there are infinitely many numbers z such that . 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