# ACOS

ACOS(number)

Returns the arc-cosine of a number.

 number The number you want the arc-cosine of.

 REMARKS
 * The inverse of this function is the COS function.* This function is also called the inverse cosine function.* The "number" is the cosine of an angle in radians.* If "number" is not numeric, then #VALUE! is returned.* The angle returned is in radians between 0 and PI.* If your argument is in degrees, multiply it by PI/180 to convert it to radians.* If your argument is in radians, multiply it by 180/PI to convert it to degrees.* If you want to convert the result from radians to degrees, multiply it by 180/PI.* You can use the COS function to return the 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 ATAN function to return the arc-tangent.* 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 =ACOS(0.5) = 1.047 2 =ACOS(-1) = 3.142 3 =ACOS(1) = 0 4 =ACOS(COS(1)) = 1 5 =ACOS(COS(0.5)) = 0.5 6 =ACOS(-0.5)*180/PI() = 120 7 =ACOS(-1)*180/PI() = 180 8 =DEGREES(ACOS(-1)) = 180 9 =ACOS(DEGREES(-0.5)*PI()/180)*180/PI() = 120 10 =ACOS(10) = #NUM! 11 =ACOS("some text") = #VALUE!

 1 - What is the arc-cosine of 0.5 radians.2 - What is the arc-cosine of -1 radians.3 - What is the arc-cosine of 1 radian.4 - This function is the inverse of the cosine function.5 - This function is the inverse of the cosine function.6 - How many degrees is the arc-cosine of -0.5 radians.7 - How many degress is the arc-cosine of -1 radians.