5. TÌM CÁC HỌ NGUYÊN HÀM SAUZZ 7Z(3X + 3) 9 DX. B) I =E 3X+1 + COS 5...

8.5. Tìm các họ nguyên hàm sau

Z

Z 7

(3x + 3) 9 dx. b) I =

e 3x+1 + cos 5x

dx.

a) I =

2 − 9x dx. c) I =

Z 4x − 1

sin 5x sin xdx.

sin 2 xdx. f) I =

d) I =

2x + 1 dx. e) I =

Lời giải.

(3x + 3) 10

a) I = 1

(3x + 3) 9 d(3x + 3) = 1

10 + C = 1

3

30 (3x + 3) 10 + C.

b) I = − 1

9

2 − 9x d(2 − 9x) = − 7

9 ln |2 − 9x| + C.

e 3x+1 dx +

e 3x+1 d(3x + 1) + 1

c) I =

cos 5xd (5x) = 1

cos 5xdx = 1

5

3 e 3x+1 + 1

5 sin x + C.

Z 3

Z

2dx − 1

2 − 3

dx =

2x + 1

2

2x + 1 d(2x + 1) = 2x − 3

2 ln |2x + 1| + C.

Z 1 − cos 2x

1

e) I =

dx = 1

cos 2xd (2x) = 1

dx − 1

2 − 1

2 x − 1

4 sin 2x + C.

4

2 dx =

2 cos 2x

f) I = 1

(cos 4x − cos 6x) dx = 1

cos 4xd (4x) − 1

cos 6xd (6x) = 1

8

12

8 sin 4x − 1

12 sin 6x + C.