He he he… I didn't think of that possibility, that she actually meant arccos
rather than cos. That should explain things.

2007/3/3, Brian Barker <[EMAIL PROTECTED]>:

At 13:35 02/03/2007 +0100, Lilian van Emden wrote:
>... there is a very irritating error
>if you use the sinus/ cosinus [...] function they give different
>value as answer (compare with my calculator, the calculator on two
>different computers), so I guess, somethings wrong with open office
>
>cos (9.17/12)=0.70(others) or 0.72(open office) ->80.30 degrees
>(others) or 82.72 degrees (open office)

You are confusing two different functions: what in English is called
the cosine function and its inverse, the arccosine function.  (Sorry
I don't know any Dutch, but I assume that "cosinus" refers to the cosine.)


I don't know any dutch either, but I am pretty sure it does, since
most languages
seems to have borrowed the word from Latin's "cosinus". sinus -> sine,
cosinus -> cosine, those words are not too far from each other…

If you are hoping to produce an angle from this calculation, what you
need must be the arccosine function, and you have evidently used this
correctly on your calculator and other computers to produce the
answer 0.70.  The arccosine function in OpenOffice Calc is ACOS,
whereas you have used the cosine function COS to produce the answer
0.72 - which is correct for cosine but not for arccosine.

As someone has already pointed out, you also have the conversion from
radians to degrees incorrect, and your answers in degrees is twice
what it should be.  The arccosine of 9.17/12 is 40.17 degrees and
=ACOS(9.17/12)*180/PI() in OpenOffice Calc correctly gives this.

Brian Barker


If ACOS doesn't work, try ARCCOS. I don't know about Dutch version, but the
cell function names are translated to Swedish (or in this case Latin…) for
the Swedish version. I also happen to know that the same goes for the
Norwegian version (function names in Norwegian). It's the same with Excel,
so I guess the reason for that it's done the same way in OpenOffice.org Calc
could be for compatibility with Excel.

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