logₓy

[Valentin Albillo]

rprosperi Wrote:The HP-75/71 mainframes include:

LOG(X) Base e Log of X
LOG10(X) Base 10 Log of X; 71B can also use LGT(X)

The HP-71B also has LN(X) as an alternate spelling.

Quote:The 71B also includes LOGP1(X) which is the value of Ln(1+x)

So, pretty complete.

Yes, in the HP-71B you have in all six log possibilities, namely LN, LOG, LOG10, LOG2, LOGP1, LGT and if you fancy log to any base you simply define:

10 DEF FNL(X,N)=LN(X)/LN(N)

and then you can use FNL(X,N) as part of any expression in a program, from the command line or in (urg!) CALC mode. Also, creating a new assembly-language keyword LOGA(X,N) in a LEX file is utterly trivial and would take just a few bytes.

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