ACOS()
Arcus cosine of the argument
- Syntax
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- ACOS (nCosine) -> nRadiant
- Arguments
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- <nCosine> the cosine of an angle
- Returns
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- <nRadiant> the angle whose cosine is <nCosine>
- Description
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- The function ACOS() is the inverse function of COS(). It takes a cosine value and returns the smallest(!) angle whose cosine equals to the argument. The return value is given in radiants (full angle equals 2*Pi - see DTOR() if you need to convert it into degress). Note, that <nCosine> must be between -1 and 1 and that <nRadiant> is always between 0 and PI().
Examples
? acos (0.0) --> PI()/2
? acos (0.5) --> 1.04719...
Tests
acos (0.0) == PI()/2
acos (sqrt(1/2)) == PI()/4
acos (1.0) == 0.0
acos (-1.0) == PI()
acos (0.0) == PI()/2 // and not -PI()/2, although cos (-PI()/2) == 0.0 !
- Status
- Ready
- Compliance
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- ACOS() is compatible with CT3's ACOS().
- Platforms
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- All
- Files
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- Source is trig.c, library is libct.
- See Also