This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.
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Trigonometric Functions
With careful attention to branch cuts, Mathematica supports trigonometric functions everywhere in the complex plane, with extensive exact and algebraic transformations, together with efficient arbitrary-precision numerical evaluation. Mathematica follows the standard mathematical convention of using radians for trigonometric function arguments.
Sin  ▪ Cos  ▪ Tan  ▪ Csc  ▪ Sec  ▪ Cot
ArcSin  ▪ ArcCos  ▪ ArcTan  ▪ ArcCsc  ▪ ArcSec  ▪ ArcCot
    
Degree (°) — constant to convert from radians to degrees
I () — , entered as Esc ii Esc ("imaginary i")
    
FullSimplify simplify trigonometric expressions
FunctionExpand reduce to algebraic forms or simpler arguments
    
TrigExpand Sin[2x]2 Sin[x]Cos[x] etc.
TrigFactor Sin[..]+Sin[..]→product of terms, etc.
TrigReduce 2 Sin[x]Cos[x]Sin[2x] etc.
TrigToExp, ExpToTrig convert between trigonometric functions and exponentials
ComplexExpand expand into real and imaginary parts
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