... 0,5 Ta có : F (4) 20 19 2. 4 C 20 19 C 20 16 0,5 Vậy F ( x ) x 20 16 0 ,25 1 2 2 I x (1 x ) dx a) x ( x x 1) dx ( x x x )dx (2, 5đ) 0 0 ,25 x x x3 ( ) ... 1;1 ) 1 0 ,25 x5 x3 ( 3x ) 1 0 ,25 52 52 104 (đvdt) ( ) 15 15 15 Tìm F(x) biết f ( x) Biết F(4) = 20 19 (1,5đ) 2x 1 F ( x ) f ( x)dx dx 2x 0 ,25 0 ,25 (2 x 1) ... 30 30 0 ,25 3 (1 cos x) sin xdx b) J sin x tanx.dx 0 0 ,25 cos x Đặt t cos x dt sin xdx Khi : x t x t 2 t2 1 J dt t 0 ,25 0 ,25 J (t )dt t 0 ,25 t2 ( ...