CÂU 4. Π Π Π Π Π/ 4 / 4 / 4 2 / 4

1 / 4 1 1x x dx xdx x d x x x x xdx

∫ ∫ ∫ ∫

+ = − = − +(1 sin 2 ) cos 2 cos 2 cos 22 2 2 20

0

0

0

0

π π

2

1 / 4

2

1= + = +sin 2 .32 4 xπ 32 4