a, x - y > 0

=> x - y + y > 0 + y

=> x > y (ĐPCM)

b, x > y

=> x - y > y - y

=> x - y > 0 (ĐPCM)

hình đâu mà làm bạn

Ta có:

1+2+3+...+x=x(x+1):2

=>x(x+1):2=aaa=a.111

=>x(x+1)=a.111.2=a.37.3.2=(6.a).37

Do x và x+1 là 2 số tự nhiên liên tiếp

=>6.a và 37 là 2 STN liên tiếp

=>6a=36=>a=6(TM) hoặc 6a=38(Loại vì a không là STN)

=>x(x+1)=36.37

>x=36

bạn viết có dấu được không . đọc khó hiểu lắm!

Tích phân  ∫ 0 1 e 2 x d x bằng

A.  e 2 - 1

B.  e 2 - 1 2

C.  2 e 2 - 1

D.  e - 1 2

Cho hình lăng trụ đứng ABC.A'B'C' có đáy ABC là tam giác đều, AB = 4cm,AA' = 5cm. Tính diện tích xung quanh, diện tích toàn phần và thể tích của hình lặng trụ ABC.A'B'C' ?

Read the passage below carefully, and then decide whether the statements are true (T), false (F) or not given (N)

Education of students who are hard of hearing or deaf may involve the use of powerful amplification devices, such as hearing aids, or it may use captions (printed words that appear on a television screen or computer monitor). Many deaf or hard of hearing students learn sign language, an organized system of gestures for communication. Others learn to speechread (lipread), a method of interpreting speech by “reading” the patterns of a person’s mouth as he or she speaks. Some deaf students receive cochlear implants, which are receivers surgically implanted behind the ear and connected to electrodes placed in the cochlea of the inner ear, enabling individuals to hear sounds to a varying degree.

Gifted children are often moved through the regular school curriculum at a faster pace than their peers. Some children with exceptionally high ability in a particular subject area may be allowed to reduce the time they spend in their other subjects to permit more time to focus on challenging content in their specialty. A high school student who is particularly gifted in math, for example, may attend advanced math classes at a local college rather than music classes at the high school. Some gifted students may also skip grades or they may enter kindergarten, high school, or college at an early age.

Question: There are many deaf students in the United States of America.

A. True

B. False

C. Not given