Re: a small correction in arithmetic expressions

[Werner LEMBERG]

> Here is a small correction in the documentation which does not affect
> the use of Lilypond, just for the sake of correctness of the
> formulas... [...]

Thanks, this is now part of a merge request, see

  https://gitlab.com/lilypond/lilypond/-/merge_requests/2291


 Werner

a small correction in arithmetic expressions

[Silvain Dupertuis]

Here is a small correction in the documentation which does not affect the use of Lilypond, 
just for the sake of correctness of the formulas...


On this page  
about the syntonic comma,the arithmetic expressionscontains a mistake and some 
inconsistency. Addition and subtraction of intervals should be represented in the 
arithmetic expression by multiplication and division operators.


So the first expression should be written “(9:8)^2 / (5:4) = 81:80” rather than “(9:8)^2 - 
5:4 = 81:80”.


For the second one, there is also a missing pair of parenthesis (or a sign 
error):

It is written as “(3:2)^4 - (2:1)^2 + (5:4)”, but should rather be written “(3:2)^4 - 
((2:1)^2 + (5:4))”. Then, replacing the addition/subtraction signs, one gets “(3:2)^4 / 
((2:1)^2 * (5:4))” as the correct arithmetic expression corresponding to the textual 
definition — which is equal to “(3:2)^4 / (2:1)^2 / (5:4)”, if we write it without the 
additional pair of parenthesis.


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