C Programming/math.h/acos

The acos function (which stands for arc cosine) is defined in. It accepts a variable, returns the arc cosine value of the variable. This function expects the values in the range of -1 to 1 and values are returned in the range 0 to PI (3.1415927). It prints NAN if a value greater than 1 is passed.

Parameters
Floating point value whose arc cosine value has to be returned.

Returns
Floating point value (arc cosine value of variable).