Re: finding ln(x)



On 19 fév, 08:27, "MQ" <michaelquinli...@xxxxxxxxx> wrote:
Hi all

I'm just wondering how a calculator finds logarithms. My idea is the
following:

If x > e, then find x/e, which is the integer portion of the result
Take the remainder and put this into the infinite series definition
for ln (ie. x - x^2/2 + x^3/3 - ....)

For logarithms of any other base b, it would just calculate ln(x)/
ln(b). Am I right or is there some more efficient algorithm?
***************************
Bonjour,
Pour les calculettes il existe des procédés genre CORDIC
rapidement convergent:suppose connus:
Ln(1,1) ; Ln(1,01) ; Ln(1,001) ...
Soit x ton nombre
x dans l'intervalle { (1,1)^n ; (1,1)^(n+1) }
alors on considère y = (x/(1,1)^n , placé par essais
dans l'intervalle {(1,01)^p ;(1,01)^(p+1) }
etc

Amicalement, Alain

.



Relevant Pages

  • Re: finding ln(x)
    ... I'm just wondering how a calculator finds logarithms. ... with/division by some fixed constants, x is restricted to an interval ... x/e is not the integer portion of ln. ...
    (sci.math)
  • finding ln(x)
    ... I'm just wondering how a calculator finds logarithms. ... If x> e, then find x/e, which is the integer portion of the result ...
    (sci.math)
  • Re: finding ln(x)
    ... I'm just wondering how a calculator finds logarithms. ... If x> e, then find x/e, which is the integer portion of the result ... Take the remainder and put this into the infinite series definition ...
    (sci.math)
  • Re: Not Just the US With Education Problems
    ... that anyone did much about logarithms anymore, ... The point is that we don't have people learning the 'skills' involved ... But again a great example---a good slide rule ... I used both a calculator and a slide rule. ...
    (talk.origins)
  • Re: Not Just the US With Education Problems
    ... that anyone did much about logarithms anymore, ... The point is that we don't have people learning the 'skills' involved ... $12 calculator can do it in an instant. ... a slide rule and we'd use our calculators to try to get the same answer. ...
    (talk.origins)