Cho các dãy số u n và v n với u n   =   1   +   1 / n ;   v n   =   5 n   –   1 .

a) Tính u n + 1 ,   v n + 1 .

b) Chứng minh u n + 1   <   u n  và v n + 1   >   v n , với mọi  n ∈ N * .

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

A. change

B. champagne

C. channel

D. choice

Mark the letter A, B, C, D on your answer sheet to indicate the word that differs from the rest in the position of the main stress.

A. support

B. project

C. believe

D. secure