terms N cons recip sqr N terms s N sqr 0 0 sqr s X s add sqr X dbl X dbl 0 0 dbl s X s s dbl X add 0 X X add s X Y s add X Y first 0 X nil first s X cons Y Z cons Y first X Z half 0 0 half s 0 0 half s s X s half X half dbl X X terms 1 1 cons 2 1 recip 1 1 sqr 1 1 s 1 1 0 0 add 2 1 2 dbl 1 1 first 2 1 2 nil 0 half 1 1 FULL ./TRS/CSR/ExSec11_1_Luc02a.trs