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Thread: OO.org spreedsheet problem

  1. #1

    Default OO.org spreedsheet problem

    I have openSuse 11.1 with the Open Office suite that comes with it.
    I've noticed a problem with the function SIN in Open Office's spreedsheet. If I try to use the SIN function on a cell that has PI, it returns 0. If I use 3.141 in that cell instead of PI, it returns 0.0062811202, use 3.1415 and it returns 0.0009819705, use 3.14159 and it returns 0.0000281235. When I checked this with Kalc, the SIN of PI returns 0.05480366514878952378.
    spopo

  2. #2
    Join Date
    Oct 2008
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    North Wales, UK
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    Default Re: OO.org spreedsheet problem

    But sinᴨ (sin(pi))= 0! So it is correct.
    3.141 is only and approximation of ᴨ and to get greater accuracy you need to continue the series like you have done.
    You should get sin(ᴨ/2) = 1
    This means that the trig functions have been set up to use radians and not degrees.
    When you checked in kalc, what value did you enter for pi? Try arcsin(1) and see what value it gives, then multiply by 2 to get the value it uses for pi.

  3. #3

    Default Re: OO.org spreedsheet problem or KALC?

    Alright,
    SIN(PI) should be 0.
    That would mean Kalc and KalcKDE4 is doing something strange which confused me. When I use the calculators, I use Constants->Mathmatics->PI and click SIN button. KalcKDE4 will show zero, but if I start KalcKDE4 and switch the deg button to rad or grad and then back to deg, it will show 0.05480366514878952378. Kalc will always show 0.05480366514878952378. They do seem to show a more correct number if the ANGLE in the calculators is set to radians. I get 1.224646799147353207e-16.

    The calculators don't have a function key for arcsin so I couldn't try what you suggested. But I did plug that into the OO spreadsheet and it returned PI.
    spopo

  4. #4
    Join Date
    Oct 2008
    Location
    North Wales, UK
    Posts
    1,114

    Default Re: OO.org spreedsheet problem or KALC?

    Ok then, 1.224646799147353207e-16 is near enough to 0.
    Because the computer works in binary, there is always going to be some error. I the main math programming languages, you normally use a double precision function for calculations where you need the accuracy.
    grads (gradians) are not the same as radians. There are 100 grads in a circle.

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