Next: Sums and Products, Previous: Complex Arithmetic, Up: Arithmetic [Contents][Index]
Octave provides the following trigonometric functions where angles are
specified in radians. To convert from degrees to radians multiply by
pi/180
or use the deg2rad
function. For example, sin (30 * pi/180)
returns the sine of 30 degrees. As an alternative, Octave provides a number of
trigonometric functions which work directly on an argument specified in
degrees. These functions are named after the base trigonometric function with
a ‘d’ suffix. As an example, sin
expects an angle in radians while
sind
expects an angle in degrees.
Octave uses the C library trigonometric functions. It is expected that these
functions are defined by the ISO/IEC 9899 Standard. This Standard is available
at: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf.
Section F.9.1 deals with the trigonometric functions. The behavior of most of
the functions is relatively straightforward. However, there are some
exceptions to the standard behavior. Many of the exceptions involve the
behavior for -0. The most complex case is atan2. Octave exactly implements
the behavior given in the Standard. Including
atan2(+- 0, 0)
returns +- pi
.
It should be noted that MATLAB uses different definitions which apparently do not distinguish -0.
Convert degrees to radians.
The input deg must be a scalar, vector, or N-dimensional array of double or single floating point values. deg may be complex in which case the real and imaginary components are converted separately.
The output rad is the same size and shape as deg with degrees
converted to radians using the conversion constant pi/180
.
Example:
deg2rad ([0, 90, 180, 270, 360]) ⇒ 0.00000 1.57080 3.14159 4.71239 6.28319
See also: rad2deg.
Convert radians to degrees.
The input rad must be a scalar, vector, or N-dimensional array of double or single floating point values. rad may be complex in which case the real and imaginary components are converted separately.
The output deg is the same size and shape as rad with radians
converted to degrees using the conversion constant 180/pi
.
Example:
rad2deg ([0, pi/2, pi, 3/2*pi, 2*pi]) ⇒ 0 90 180 270 360
See also: deg2rad.
Compute the hyperbolic secant of each element of x.
See also: asech.
Compute the hyperbolic cosecant of each element of x.
See also: acsch.
Compute the hyperbolic cotangent of each element of x.
See also: acoth.
Compute the inverse hyperbolic sine for each element of x.
See also: sinh.
Compute the inverse hyperbolic cosine for each element of x.
See also: cosh.
Compute the inverse hyperbolic tangent for each element of x.
See also: tanh.
Compute the inverse hyperbolic secant of each element of x.
See also: sech.
Compute the inverse hyperbolic cosecant of each element of x.
See also: csch.
Compute the inverse hyperbolic cotangent of each element of x.
See also: coth.
Compute atan (y / x) for corresponding elements of y and x.
y and x must match in size and orientation. The signs of elements of y and x are used to determine the quadrants of each resulting value.
This function is equivalent to arg (complex (x, y))
.
Octave provides the following trigonometric functions where angles are specified in degrees. These functions produce true zeros at the appropriate intervals rather than the small round-off error that occurs when using radians. For example:
cosd (90) ⇒ 0 cos (pi/2) ⇒ 6.1230e-17
Compute the sine for each element of x in degrees.
Returns zero for elements where x/180
is an integer.
Compute the cosine for each element of x in degrees.
Returns zero for elements where (x-90)/180
is an integer.
Compute the tangent for each element of x in degrees.
Returns zero for elements where x/180
is an integer and
Inf
for elements where (x-90)/180
is an integer.
Compute atan (y / x) in degrees for corresponding elements from y and x.
Next: Sums and Products, Previous: Complex Arithmetic, Up: Arithmetic [Contents][Index]