How to simplify factorial before calculating the result

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Christophe Croisetière 2021-9-29

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https://ww2.mathworks.cn/matlabcentral/answers/1463469-how-to-simplify-factorial-before-calculating-the-result

编辑： James Tursa 2021-9-29

Hi, I'm trying to calculate (2189!/(2165!*24!))/(2190!/(2165!*25!)). MathLab is telling me it's NaN because of the Inf/Inf result but i know the answer is around 1/438. Is there a way to tell MathLab to simplify the factorials before calulating their values.

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James Tursa 2021-9-29

编辑：James Tursa 2021-9-29

Is it only this particular calculation you are interested in (which easily reduces to 25/2190 by inspection ... not close to your claimed 1/438), or is this simply an example of a more generic calculation?

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Matt J 2021-9-29

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https://ww2.mathworks.cn/matlabcentral/answers/1463469-how-to-simplify-factorial-before-calculating-the-result#answer_798074

在 MATLAB Online 中打开

nchoosek(2189,24)/nchoosek(2190,25),
Warning: Result may not be exact. Coefficient is greater than 9.007199e+15 and is only accurate to 15 digits
Warning: Result may not be exact. Coefficient is greater than 9.007199e+15 and is only accurate to 15 digits
ans = 0.0114