【正文】
s1c o s22c o s 2 ????.2t a n,2c os,2s i n,III,53s i n 8 ???????? 求設(shè)例,III,53s i n ??????解:2)53(1 ???? ?????? 2s i n1c o s54??????? c o ss i n22s i n2524?22 )53(21s i n212c os ????????257?25725242c o s2s i n2t a n ?????724?)54()53(2 ????????? c o ss i n22s i n????? 22 s i nc o s2c o s???? 2s i n212c o s1c o s22c o s 2 ????)10t a n1(50s i n 9 00 ?化簡例)10c