【正文】
vxxxxv?????xxvxxvxuxxvxxuxxuxyxxx ??????????????????????)()(l i m)()()()(l i ml i m000)()()()( 39。39。s i n)( s i ns i n)( ????解:xxxxx22s i nco ss i n2 ??處的導(dǎo)數(shù)在點(diǎn)求例 2 ???? xxxy22239。239。39。 xvxuxvxu ??39。)3(2)3()3(1???????xxxxy解:222)3(36?????xxx6114424)39(3189|233