Classical Runge-Kutta Sample Test Problem

       Approximate the solution of the IVP

               y'   =   sqrt(x) + cos(y)
               y(2) = 3


       x0 =   2.0000
       xf =   6.0000
       h  =   1.0000
       y0 =   3.0000


         n        x                y
      ***************************************

         0    2.0000000     3.0000000000000
         1    3.0000000     3.6013709980265
         2    4.0000000     4.9967303101055
         3    5.0000000     7.7771497442982
         4    6.0000000     9.4713818321494