### ATAN(number)

Returns the arc-tangent of a number.

 number The number you want the arc-tangent of.

#### Remarks

 * The inverse of this function is the TAN function.* This function is also called the inverse tangent function.* The "number" is the angle in radians.* If "number" is not numeric, then #VALUE! is returned.* The returned angle is given in radians between -PI/2 and PI/2.* If your argument is in degrees, multiply it by PI/180 to convert it to radians.* If you want to convert the result from radians to degrees, multiply it by 180/PI.* You can use the TAN function to return the tangent.* You can use the ACOS function to return the arc-cosine.* You can use the ACOT function to return the the arc-cotangent.* You can use the ASIN function to return the arc-sine.* You can use the DEGREES function to convert from radians to degrees.* For a working example refer to the Quant > Trigonometric Functions page.* For the Microsoft documentation refer to support.microsoft.com

 A 1 =ATAN(0) = 0.00 2 =ATAN(1) = 0.785 3 =ATAN(-1) = -0.785 4 =ATAN(1)*180/PI() = 45 5 =DEGREES(ATAN(0.5)) = 27 6 =DEGREES(ATAN(1)) = 45 7 =ATAN(-50) = -1.551 8 =ATAN(TAN(0.5)) = 0.5 9 =ATAN(100) = 1.561 10 =ATAN(3/2)=ATAN2(2,3) = -1.000 11 =ATAN("some text") = =ATAN("some text")

 5 - How many degrees is the arc-tangent of -0.5 radians.