Exercise 7.9

2/0 2x x +∫ (Put x + 2 = t2) 5. 2 sin 1 cos x dx x π +∫ 6. 20 4 - dx x x+∫ 7. 21 2 5 dx x x− + +∫ 8. 2 2 1 1- xe dxx x     ∫ Choose the correct answer in Exercises 9 and 10.

1 4 ( )x x dx x − ∫ is (A) 6 (B) 0 (C) 3 (D) 4 10. If f (x) = 0 sin x t t dt∫ , then f ′(x) is (A) cosx + x sin x (B) x sinx (C) x cosx (D) sinx + x cosx