例2求函数y= In tan(+)的导数 24 1解设y=lna,u=toy,v?4 y?=(n u.(tgv)y( 24x 2 u cOs v g(2+4)c0S(+4)2 - secx 2021/2/20 sin(x +2) cos x 152021/2/20 15 2 4 ln , ,  = = = + x 设 y u u tgv v x u v x x y u tgv ) 2 4  = (ln ) ( ) ( +   )] . 2 4 [例2] 求函数 ln[tan( 的导数  = + x y [解] 2 1 cos 1 1 2 =   u v 2 1 cos ( ) 1 ( ) 1 2 4 2 2 4  +  + = x  x  t gsin( ) 1 2  + = x cos x 1 = = secx