Functions > Trigonometric, Log, and Exponential > Inverse Trigonometric Functions
  
Inverse Trigonometric Functions
asin(z), acos(z), atan(z), asec(z), acsc(z), acot(z)—Return the value, in radians, of the arcsine, arccosine, arctangent, arcsecant, arccosecant, and arccotangent respectively. The returned value is the angle whose sin, cos, tan, etc, is z. It is taken from the principal branch of these functions. The result returned by acot is between 0 and π if z is real, or it is the principal value if z is complex.
The atan function is related to polar angles.
Arguments
z is a dimensionless scalar or a vector of scalars.