$ZLN
Returns the natural logarithm of the specified number.
Synopsis
$ZLN(n)
Parameter
| Argument | Description |
|---|---|
| n | Any positive nonzero number, which can be specified as a value, a variable, or an expression. |
Description
$ZLN returns the natural logarithm (base e) value of n.
Specifying zero or a negative number results in an <ILLEGAL VALUE> error.
The corresponding natural logarithm power function is $ZEXP.
Examples
The following example writes the natural log of the integers 1 through 10:
FOR x=1:1:10 {
WRITE !,"The natural log of ",x," = ",$ZLN(x)
}
QUIT
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returns:
The natural log of 1 = 0 The natural log of 2 = .6931471805599453089 The natural log of 3 = 1.098612288668109691 The natural log of 4 = 1.386294361119890618 The natural log of 5 = 1.609437912434100375 The natural log of 6 = 1.791759469228055002 The natural log of 7 = 1.945910149055313306 The natural log of 8 = 2.079441541679835929 The natural log of 9 = 2.197224577336219384 The natural log of 10 = 2.302585092994045684
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The following example shows the relationship between $ZLN and $ZEXP:
SET x=$ZEXP(1) ; x = 2.718281828459045236 WRITE $ZLN(x)
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returns 1.
WRITE $ZLN(0)
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issues an <ILLEGAL VALUE> error.