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- atan2()
### atan2()

# atan2()

atan2(expr0,expr1) ⇒ number

The atan2() function returns the inverse tangent or arctangent of the quotient of its arguments, expr0/expr1, as a number. The result is returned as a radian angle. The corresponding mathematical notations are:

atan2(y,x)

atan2(y,x) returns a numeric value between and representing the angle theta of an (

*x*,*y*) point. This is the counterclockwise angle, measured in radians, between the positive*X*axis and the point (*x*,*y*). Note that the arguments to this function pass the*y*-coordinate first and the*x*-coordinate second.Use the calculator at the top right of the window to find the inverse tangent of a number. Click the [2

^{nd}] key at the top left of the keypad, then click [atan], then enter*x*, ',' and*y*.## Scientific calculator

## References