Rút gọn A:

A= ( \(\frac{^{x^2+x-4}}{x^2-2\text{x}-3}\) + \(\frac{x-1}{3-x}\)) : ( 1 - \(\frac{x-3}{x-2}\))

Cho a, b là hai số bất kì, chứng tỏ rằng: \(\frac{a^2+b^2}{2}\) \(\ge\)ab

Cho x+y = 1. Tìm giá trị nhỏ nhất của biểu thức M = x⁴ + y⁴.

Làm topic Tiếng Anh hộ ^^

Unit 7: POLLUTIONS

- What are the cause and effects of air pollution? What are the solutions to this problem?

- What are the cause and effects of water pollution? What are the solutions to this problem?

- What are the cause and effects of noise pollutions? What are the solutions to this problem?

- If you were the president, what would you do to help the environment?

Trong bài Chiều Dời Đô:

- Theo tác giả, Đại La có những thuận lợi gì để chọn làm kinh đô của đất nước ( về lịch sử, về vị trí địa lí, về thế đất, về chính trị văn hóa)? Em có nhận xét gì về đưa luận chứng và cách lập luận của tác giả? ( dẫn chứng toàn diện, xác thực, câu văn biền ngẫu nhấn mạnh)

- Với việc đưa ra các dẫn chứng trên, tác giả muốn khẳng định điều gì?

Thả một vật có khối lượng là 8.5 kg với độ cao là 9m.

a. Lực nào đã thực hiện công

b. Tính công của vật

c. Nếu nâng vật đó bằng ròng rọc với cùng khối lượng và độ đó thì cần một lực bao nhiêu Niu tơn.

Kim loại Na có khối lượng riêng là 0.79g/cm³ . Tính thể tích mol của Na biết: Khối lượng mol của Na= 23 (g/mol)

Hãy rút gọn biểu thức:

a. (2a-4)(2b+4)

b. \(^{ }\left(-x-y^{ }\right)\)\(^2\)

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

          Leonardo was the son of a wealthy Florentine public official and a peasant woman. In the mid- 1460s, the family settled in Florence, where Leonardo was given the best education that Florence could offer. He rapidly advanced socially and intellectually. He was handsome, persuasive in conversation, and a fine musician and improviser. About in 1466 he apprenticed as a studio boy to Andrea Del Verrocchio. In Verrocchio’s workshop, Leonardo was introduced to many activities, from the painting of altarpieces and panel pictures to the creation of large sculptural projects. In 1472, he was entered in the painter’s guild of Florence, and in 1476, he was still mentioned as Verrocchio’s assistant. In Verrocchio’s Baptism of Christ, the kneeling angel at the left of the painting is by Leonardo.

          In 1478, Leonardo became an independent master. His first commission, to paint an altarpiece for the chapel of the Palazzo Vecchino, the Florentine town hall, was never executed. His first large painting, The Adoration of the Magi, left unfinished, was ordered in 1481 for the Monastery of San Donato a Scopeto, Florence. Other works ascribed to his youth are the so-called Benois Madonna, the portrait Ginerva de 'Benci, and the unfinished Saint Jerome,

          In 1482, Leonardo’s career moved into high gear when he entered the service of the duke of Milan, Ludovico Sforza, having written the duke an astonishing letter in which he stated that he could build portable bridges; that he knew the techniques of constructing bombardments and of making cannons; that he could build ships as well as armored vehicles, catapults, and other war machines; and that he could execute sculpture in marble, bronze, and clay. He served as a principal engineer in the duke’s numerous military enterprises and was so active also as an architect. In addition, he assisted the Italian mathematician Luca Pacioli in the celebrated work Divina Proportione.

          Evidence indicates that Leonardo had apprentices and pupils in Milan, for whom he probably wrote the various texts later compiled as Treatise on Painting. The most important of his own paintings during the early Milan period was The Virgin of the Rocks, two versions of which exist; he worked on the compositions for a long time, as was his custom, seemingly unwilling to finish what he had begun.

          From 1495 to 1496, Leonardo labored on his masterpiece, The Last Super, a mural in the refectory of the Monastery of Santa Maria Delle Grazie, Milan. Unfortunately, his experimental use of oil on dry plaster was technically unsound, and by 1500 its deterioration had begun. Since 1726 attempts have been made, unsuccessfully, to restore it; a concerted restoration and conservation program, making use of the latest technology, was begun in 1977 and is reversing some of the damage. Although much of the original surface is gone, the majesty of the composition and the penetrating characterization of the figures give a fleeting vision of its vanished splendor.

          During his long stay in Milan, Leonardo also produced other paintings and drawings, most of which have been lost, theater designs, architectural drawings, and models for the dome of Milan Cathedral. His largest commission was for a colossal bronze monument to Francesco Sforza, father of Ludovico, in the courtyard of Castello Sforzesco. In December 1499, however, the Sforza family was driven from Milan by French forces; Leonardo left the statue unfinished and he returned to Florence in 1500.

What is NOT mentioned as a creation of Leonardo da Vinci’s while he was in Milan? 

A. theatre designs

B. architectural drawings

C. models of bronze horses

D. models for church domes