Result of:   j=0 indicates x too small
            j=100 indicates x too large
    locate      j      xx(j)     xx(j+1)
   -90.0000     0   lower lim  -72.948730
   -80.0000     0   lower lim  -72.948730
   -70.0000    27  -70.142578  -69.944801
   -60.0000    52  -60.536263  -59.845959
   -50.0000    63  -50.663933  -49.467468
   -40.0000    70  -40.884548  -39.186684
   -30.0000    75  -31.478916  -29.298817
   -20.0000    79  -22.064632  -19.401852
   -10.0000    83  -10.565994   -7.313683
     0.0000    86   -0.300194    3.478455
    10.0000    88    7.450874   11.626930
    20.0000    90   16.017128   20.632423
    30.0000    92   25.484306   30.584999
    40.0000    94   35.947151   41.584282
    50.0000    96   47.510437   53.740379
    60.0000    97   53.740379   60.289795
    70.0000    99   67.174942   74.413162
    80.0000   100   74.413162   upper lim
    90.0000   100   74.413162   upper lim