find the lowest common denominator

[Hamada-77]

hello
how can i find the lowest common denominator of two numbers with Hp prime ?
thanks

[Didier Lachieze]

I'm not sure there is a build-in function providing the lowest common denominator.
So here is a small program doing that:

Code:

EXPORT LCD(N,M)
BEGIN
 LOCAL l:={};
 l:=INTERSECT(mat2list(idivis(N)),mat2list(idivis(M)));
 RETURN l(MIN(SIZE(l),2));
END;

[Joe Horn]

(01-15-2018 12:53 PM)Didier Lachieze Wrote:  I'm not sure there is a build-in function providing the lowest common denominator.

There is: it's the lcm function (lowest common multiple). In CAS, it works on integers of any length.

lcm(12,18) --> 36
1/12+1/18 --> 5/36

It also works on polynomials, not just integers.

[Didier Lachieze]

Good point, I misunderstood the request as beeing for the lowest common divisor.

[john gustaf stebbins]

I'm getting to go through this basic math with my kids now.

I think the least common divisor can be found with the "1" function.

;^)

On the 50g, this was actually function of sort, at least a token so that this commonly used number parsed faster than a number literal. Don't know that they have done the same with the Prime.

-jgs