Subject: Base 10 logarithm

66. *****
 Q: How do I get a base 10 logarithm in TP?

 A: Just define
     function log (x : real) : real;
     begin log := ln(x) / ln(10); end;
This result is based on some elementary math. By definition
y = log(x) in base 10 is equivalent to x = 10^y (where the ^
indicates an exponent). Thus ln(x) = y ln(10) and hence
y = ln(x) / ln(10).
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