=====log=====
Syntax:

<code>
    #include <cmath>
    double log( double num );
</code>
The function log() returns the natural (base e) logarithm of num. There's a
domain error if num is negative, a range error if num is zero.
In order to calculate the logarithm of x to an arbitrary base b, you can use:

<code>
    double answer = log(x) / log(b);
</code>

C++ also provides the following overloaded forms:
<code>
    #include <cmath>
    float log( float num ); // same as logf() in C99
    long double log( long double num ); // same as logl() in C99
</code>

Related Topics: [[exp]], [[log10]], [[pow]], [[sqrt]]