The ACOS function returns the inverse cosine (arccosine) of a number.
ACOS(num)
num: A number value. num must be in the range –1 to 1.
Notes
The ACOS function takes a cosine value and returns a corresponding angle. The resulting angle is expressed in radians, in the range 0 to π (pi). To see the resulting angle in degrees instead of radians, wrap this function in the DEGREES function; that is, =DEGREES(ACOS(num)).
Examples |
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=ACOS(SQRT(2)/2) returns 0.785398163397448, which is approximately π/4. =ACOS(0.54030230586814) returns 1. =DEGREES(ACOS(.5)) returns 60, the degree measure of an angle that has a cosine of 0.5. |