8.(sin x+cos x dx=d(cos x+sin x) 9(2x+=dx+x)10a d tanx COS x 11 d cotx 例8求下列各式的不定积分 (2) tax ()解a d(3-2 3-2x2J3-2 3-2 (2)解∫ ax d(-3x+1) e 结论1:(ax+b)=(ax+b)d(ax+b)6 例8 求下列各式的不定积分 3 2 1 (2) . x e dx 1 ( 2 ) (1) 3 2 2 3 2 dx d x x x 解 3 3 2 2 1 1 3 2 2 (2) 1 3 x x e dx e d x 解 ( ) 结论1: 1 f (ax b)dx f (ax b)d(ax b) a 8.(sin x cos x)dx d(cos x sin x) 2 9.(2x1)dxd(x x) 2 10. tan cos dx d x x 2 11. cot sin dx d x x 1 (3 2 ) 2 3 2 d x x 1 ln 3 2 2 x C 3 2 2 1 3 x e C (1) ; 3 2 dx x