18 COS7X COS9X CCOS9X COS7X CC

Câu 102:



cos8x.sin xdx

^bằng:

12

A.

1

sin 8x.cosx

C

8



B.

1



8



cos7x

cos9x

C

cos9x

cos7x

C

C.

1

1

18



14



14



18



D.

1

1