Thread: Original sin()

  1. #1
    Registered /usr
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    Newport, South Wales, UK

    Original sin()


    Does anyone know how the sin() function works, i.e. how it finds the sine of the input angle computationally?

  2. #2
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    Sep 2001
    I don't know for sure, and have nothing to back me up, but I'd bet it's a fairly simple lookup system, probably based on the repetitive nature of the unit circle.

  3. #3
    I like code Rouss's Avatar
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    Apr 2004
    My guess would be that it uses the power series equivilant of sin(x)... I think I heard somewhere that's how a calculator finds it. But that's just a guess.

  4. #4
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    Jan 2005
    Triangle ABC has three sides AB, BC and AC. If ABC is a right angle triangle, then Sin(A) = BC/AB ...(sin(x) = opposite / hypostenuse). There is only one hypotenuse so naturally, A != 90 degrees.
    Last edited by duvernais28; 02-22-2005 at 01:11 AM.

  5. #5
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    Tucson, Arizona

  6. #6
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    Jan 2005
    Well, you could go that route if you're familiar with calculas but I think the basics still apply. It's been been too long since I've looked at that kind of

    This should be sufficient.
    Last edited by duvernais28; 02-22-2005 at 01:37 AM.

  7. #7
    and the hat of int overfl Salem's Avatar
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    Aug 2001
    The edge of the known universe
    Lookup tables
    Polynomial expansion
    Maths co-processor instruction

    All viable ways depending on your individual circumstances of the need for speed, accuracy and available processing power.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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