Re: Emacs Calc - Npr and NCR functions

[Tassilo Horn <tassilo@member.fsf.org>]

Peter Dyballa <Peter_Dyballa@Web.DE> writes:

Hi Peter,

>>> Does anyone know how to access the Npr and Ncr functions with Emacs
>>> calc?
>> 
>> What are those functions?
>
> Combinatorics, Binomial coefficients, permutations, combinations. Some
> desk or pocket calculators provide such functions.
>
> I think nPr is n!/(n-k)! and nCr is n!/k!(n-k)!...

Ok, so the functions and keys are:

,----[ (info "(calc)Combinatorial Functions") ]
|    The `k c' (`calc-choose') [`choose'] command computes the binomial
| coefficient `N'-choose-`M', where `M' is the number on the top of the
| stack and `N' is second-to-top.  If both arguments are integers, the
| result is an exact integer.  Otherwise, the result is a floating-point
| approximation.  The binomial coefficient is defined for all real
| numbers by `N! / M! (N-M)!'.
`----

,----[ (info "(calc)Combinatorial Functions") ]
|    The `H k c' (`calc-perm') [`perm'] command computes the
| number-of-permutations function `N! / (N-M)!'.
`----

Bye,
Tassilo