). Cho ma trận 3 2 2 2 2 2 2 1 2 2 2 1 2 m m m m m m A  − − − −    + − − −   = − − . a. Chéo hóa ma trận A . b. Từ kết quả câu a, hãy tính 10 A . cho m=2, n=6

). Cho ánh xạ tuyến tính 3 3 f : ℝ ℝ → và hai cơ sở của 3 ℝ : B b b n b = = = − = { 1 2 3 (1,3,3), ( ,6,5), (1,2,2)} , C c = − {c n c 1 2 3 = = = ( ), ( ), ( ) 2, 3,3 5, 1, 5 − + − − 1,0,1 } . Biết: 1 f b( ) ( 5,6,4) = − , 2 f b( ) ( 8,5,2) = − , 3 f b( ) ( 9, 2, 5) = − − − . a. Tìm ma trận 3 [ ] A f E = , từ đó suy ra biểu thức của 1 2 3 f x x x ( , , ). 2/2 b. Tìm ma trận [ ]B f . c. Từ [ ]B f , hãy tính ma trận [ ]C B f . d. Cho vector ( 2,3, ) x n = − , hãy tính [ ]B x và suy ra [ ( )]C f x . cho m=2. n=6

Tìm hệ số của x^3 trong đa thức sau a) P(x)=(x^3-3x^2+2x+1).(-x^2)-x(2x^2-3x+1) b)Q(x)=[5x^2-a(x+a)]-[3(a^2-x^20+2ax]=[2ax-4(a+2ax^2)]

). Trong không gian vector 3 ℝ cho hai hệ vector U u m u u = { 1 2 3 = − = = ( 2,2,5); (2,1,3); (3,1,3)} , V v m v m v = − −= { 1 2 3 = = ( ( 1,2,1); ,2,1); ( 1,7,4)} . a. Chứng tỏ U , V là hai cơ sở của 3 ℝ . b. Cho x m = − ( ,2, 3), tìm tọa độ của x theo cơ sở V . c. Tìm U V P → và V U P → . d. Sử dụng công thức đổi tọa độ, tìm tọa độ của x theo cơ sở U cho m=2, n=6

Lập dàn ý thuyết minh chiếc nón lá. Ngắn nhưng đủ ý

cho m=2, n=6 Cho hệ các vector U = − − + − {(1,2, ); (2,3, 1);(1,0,2 n n n (0, 1,1 ); ) n } . a. Tìm số chiều và một cơ sở W của không gian con sinh bởi hệ vector U . b. Tìm tham số k để 2 u k = + (2,3, 1) là một tổ hợp tuyến tính của W , và suy ra [ ]W u .

so sánh các số hữu tỉ sau bằng cách nhanh nhất: a. -15/7 và -6/5 b. 278/37 và 287/46 c. -157/623 và -47/213

1. She was rather doubtful ....... the wisdom of eating the seafood 2. She was still feeling very sad.........her father's death

Hurry up! The train (come) tại sao lại làm vậy

My Bedroom Robert Robert likes his room to be tidy, but it's difficult as it's his brother's bedroom too. When Robert is alone in the room he does his homework or listens to music. On the walls there are a few small posters. Robert wants to have more, and to paint the walls yellow, but his mother doesn't agree. There are photographs of family holidays and of his sister's children. 'I like my room best when they're here. It gets untidy, but I don't mind.' James James's bedroom is painted in his favourite colour, yellow. He loves rugby, and there are several photos of him playing in the school team. 'After school I like to come up here to play computer games. My room's like my safe place. I can relax here.' james keeps his room tidy. His school work is on one shelf, and on another he has all his books. Harry 'After school I come up here and chat to everyone I know on the computer,' says Harry. 'I never work in here - I study in the kitchen.' He has a big desk with a laptop in the middle, a PC on one side and a lamp on the other. On the walls there are two posters of his favourite tennis stars. 'I don't do much sport but I like watching tennis.' __________________________________________ EXAMPLE 0. Whose room has yellow walls? Robert James Harry THE CORRECT ANSWER IS (B) __________________________________________ 1. Who has more than one computer in his room? Robert James Harry 2. Who would like more pictures on the walls? Robert James Harry 3. Who has pictures of himself doing sport? Robert James Harry 4. Who shares his room with someone else? Robert James Harry 5. Who talks to friends when he's in his room? Robert James Harry 6. Who sometimes has visitors to his room? Robert James Harry 7. Who studies in his bedroom? Robert James Harry