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Reference for unit 'System' (#rtl)

Ln

Calculate logarithm

Declaration

Source position: mathh.inc line 110

function Ln(

d: ValReal

):ValReal;

Ln returns the natural logarithm of the Real parameter X. X must be positive.

An run-time error will occur when X is negative.

Program Example37;

{ Program to demonstrate the Ln function. }

begin
  Writeln (Ln(1));      { Prints 0 }
  Writeln (Ln(Exp(1))); { Prints 1 }
end.