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LETTERatanULETTER Arctangent function.

Overview
#include <math.h>

d = atan(x);

double d; // result
double x; // angle

Portability
ANSI

Description
The arctangent function is the opposite to the tangent function. It expects its argument within -PI < x < +PI and will return values within -PI/2 < y < +PI/2.

Note
Of course all trigonometric functions require the angle be expressed in radians. Pass the angle "w" expressed in degrees to
x = PI/180 * w
to receive its equivalent in radians in "x".

See also
tan , acos , asin