This is documentation for an old release of NumPy (version 1.3.). Read this page in the documentation of the latest stable release (version > 1.17).
Trigonometric sine, element-wise.
Parameters: | x : array_like
|
---|---|
Returns: | y : array_like
|
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 axis,
makes an angle at the origin (measured counter-clockwise from that
axis), and departs from the origin. The
coordinate of
the outgoing ray’s intersection with the unit circle is the sine
of that angle. It ranges from -1 for
to
+1 for
The function has zeroes where the angle is
a multiple of
. Sines of angles between
and
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))
>>> plt.xlabel('Angle [rad]')
>>> plt.ylabel('sin(x)')
>>> plt.axis('tight')
>>> plt.show()