HP Prime Forum

Full Version: Four quadrant inverse tangent function
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
This HP Prime function calculates an angle between 0 and 2 pi radians using the sin and cosine of the angle provided by the user.

It is called ATAN3 because FORTRAN has a function called ATAN2 that calculates an angle between plus and minus pi.

The syntax of this function is a follows;

EXPORT ATAN3(a, b)

// four quadrant inverse tangent

// input

// a = sine of angle
// b = cosine of angle

// output

// 0 =< angle <= 2 pi

////////////////////
Reference URL's