This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.

# ArcCos

 ArcCos[z]gives the arc cosine of the complex number .
• Mathematical function, suitable for both symbolic and numerical manipulation.
• All results are given in radians.
• For real between and , the results are always in the range to .
• For certain special arguments, ArcCos automatically evaluates to exact values.
• ArcCos can be evaluated to arbitrary numerical precision.
• ArcCos automatically threads over lists.
• ArcCos[z] has branch cut discontinuities in the complex plane running from to and to .
 Out[1]=

 Out[1]=

 Out[1]=
 Scope   (6)
Evaluate numerically:
Evaluate for complex arguments:
Evaluate to high precision:
The precision of the output tracks the precision of the input:
The precision of the output can be much less than the precision of the input:
Simple exact values are generated automatically:
ArcCos threads element-wise over lists and matrices:
ArcCos can deal with real-valued intervals from :
Infinite arguments give symbolic results:
ArcCos can be applied to power series:
Find series expansions at branch points and branch cuts:
ArcCos threads over explicit lists as well as over sparse arrays:
ArcCos is a numerical function:
 Applications   (3)
Plot the real and imaginary part of ArcCos:
Plot the Riemann surface of ArcCos:
Find the angle between two vectors:
Compose with the inverse function:
Use PowerExpand to disregard multivaluedness of the ArcCos: