# xarray.ufuncs.sin¶

xarray.ufuncs.sin = <xarray.ufuncs._UFuncDispatcher object>

xarray specific variant of numpy.sin. Handles xarray.Dataset, xarray.DataArray, xarray.Variable, numpy.ndarray and dask.array.Array objects with automatic dispatching.

Documentation from numpy:

sin(x, /, out=None, *, where=True, casting=’same_kind’, order=’K’, dtype=None, subok=True[, signature, extobj])

Trigonometric sine, element-wise.

Parameters
xarray_like

Angle, in radians ($$2 \pi$$ rad equals 360 degrees).

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 freshly-allocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.

wherearray_like, optional

Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone.

**kwargs

For other keyword-only arguments, see the ufunc docs.

Returns
yarray_like

The sine of each element of x. This is a scalar if x is a scalar.

Notes

The sine is one of the fundamental functions of trigonometry (the mathematical study of triangles). Consider a circle of radius 1 centered on the origin. A ray comes in from the $$+x$$ axis, makes an angle at the origin (measured counter-clockwise from that axis), and departs from the origin. The $$y$$ coordinate of the outgoing ray’s intersection with the unit circle is the sine of that angle. It ranges from -1 for $$x=3\pi / 2$$ to +1 for $$\pi / 2.$$ The function has zeroes where the angle is a multiple of $$\pi$$. Sines of angles between $$\pi$$ and $$2\pi$$ are negative. The numerous properties of the sine and related functions are included in any standard trigonometry text.

Examples

Print sine of one angle:

>>> np.sin(np.pi/2.)
1.0


Print sines of an array of angles given in degrees:

>>> np.sin(np.array((0., 30., 45., 60., 90.)) * np.pi / 180. )
array([ 0.        ,  0.5       ,  0.70710678,  0.8660254 ,  1.        ])


Plot the sine function:

>>> import matplotlib.pylab as plt
>>> x = np.linspace(-np.pi, np.pi, 201)
>>> plt.plot(x, np.sin(x))