=====log===== Syntax: #include double log( double num ); 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: double answer = log(x) / log(b); C++ also provides the following overloaded forms: #include float log( float num ); // same as logf() in C99 long double log( long double num ); // same as logl() in C99 Related Topics: [[exp]], [[log10]], [[pow]], [[sqrt]]