Find roots



>>>>> "Richard" == Richard Hennessy <rich.hennessy at verizon.net> writes:

    Richard> This challenge might be interesting to some people.  Try to find the
    Richard> three real roots to log(x^3-x*78+90)+x.  I had a hard time with it.

Because of the three real zeroes of x^3-x*78+90, the log function
makes it difficult.  I transformed the equation to
(x^3-x*78+90)*exp(x)=1 and found the roots of that.  A plot of the
original function gives a rough idea of where the roots are:  near -6,
1, and 8.

Ray