nag_zero_nonlin_eqns_deriv_easy (c05rbc) Example Program Results
(User-supplied callback fcn, first invocation.)
Final approximate solution

     -0.5707      -0.6816      -0.7017
     -0.7042      -0.7014      -0.6919
     -0.6658      -0.5960      -0.4164