acos()

Returns the arccosine (inverse cosine) of the given value in radians.

acos(value)

• The arccosine of the given value in radians.
• Returns None if the input is outside the range [-1, 1].

acos(1);     // returns 0

acos(0);     // returns pi()/2

acos(-1);    // returns pi()

pi
sin
asin
cos
acos
tan
atan
atan2
rad2deg
deg2rad