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## 9.135 Ln

### Synopsis

    function Ln (x: Real): Real;

or

    function Ln (z: Complex): Complex;

### Description

The natural logarith ``Ln'` is the logarithm with base e, where e is the Euler number e = Exp (1) = 2.718281828...

### Conforming to

The function ``Ln'` is defined in ISO-7185 Pascal; its application to complex values is defined in ISO-10206 Extended Pascal.

### Example

    program LnDemo;
    var
      z: Complex;
    begin
      z := Cmplx (1, 1);
      z := Ln (z)  { yields Ln (SqRt (2)) + i * Pi / 4 }
                   { since Ln (i * x) = Ln Abs (x) + i * Arg (x) }
    end.

### See also

This document was generated by Frank Heckenbach on May, 10 2002 using texi2html