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See the recommended documentation of this function
atan
2-quadrant and 4-quadrant inverse tangent
Calling Sequence
phi=atan(x) phi=atan(y,x)
Arguments
- x
real or complex scalar, vector or matrix
- phi
real or complex scalar, vector or matrix
- x, y
real scalars, vectors or matrices of the same size
- phi
real scalar, vector or matrix
Description
The first form computes the 2-quadrant inverse tangent, which is the
inverse of tan(phi)
. For real x
,
phi
is in the interval (-pi/2, pi/2). For complex
x
, atan
has two singular, branching
points +%i
,-%i
and the chosen branch
cuts are the two imaginary half-straight lines [i, i*oo) and (-i*oo,
-i].
The second form computes the 4-quadrant arctangent (atan2 in
Fortran), this is, it returns the argument (angle) of the complex number
x+i*y
. The range of atan(y,x)
is
(-pi, pi].
For real arguments, both forms yield identical values if
x>0
.
In case of vector or matrix arguments, the evaluation is done
element-wise, so that phi
is a vector or matrix of the
same size with phi(i,j)=atan(x(i,j))
or
phi(i,j)=tan(y(i,j),x(i,j))
.
Examples
Authors
- B.P.
- L.V.D. (authors of the complex atan function).
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