Cho tam giác ABC có các đường cao ', ', 'AA BB CC đồng quy tại H. Chứng minh rằng 6 AH BH CH A H B H C H + + ≥ ′ ′ ′ . Xin chần thành được sự giúp đỡ! x 1 x x 1 x2 x x x 1 1/ Cho biểu thức M = , với x > x x x x x x x a/ Rút gọn M chứng minh M > b/ Với giá trị x N = có giá trị nguyên M 2/ Cho x > 0, y > thỏa x + y = CMR: 8(x4 + y4) + 5 xy HD: Bài a/ b/ Bài 3b Bài 4b A M K H B Bài L C Giải giúp em với . Tính tích phân 1 2 1 ( 1)( 1) x dx e x − + + ∫ Nhờgiúp đỡ! 1) Although Tom was a poor student, he studied very well. => In spite of … being a poor student, Tom studied very well. 2) Although the weather was bad, she went to school on time. => Despite …. The bad weather, she…. 3) My mother told me to go to school although I was sick. => In spite of …. My sickness, my mother told me to go to school. 4) Tom was admitted to the university although his grades were bad. => Despite …. Tom’s bad grade, he was admitted to the university. 5) Although she has a physical handicap, she has become a successful woman. => Despite ….having a physical handicap, she has become a successful woman 6) In spite of his good salary, Tom gave up his job. => Although…. Tom’s salary was good, Tom gave up his job 7) Though he had not finished the paper, he went to sleep. => In spite of ……not having finished the paper, he went to sleep 8) In spite of the high prices, my daughter insists on going to the movies. => Even though ……the prices are high, my daughter insists on going to the movies 9) Athough his dog was crashed into by the car, he didn't feel worry about it. => Despite…. despite the fact that his dog was crashed into by the car, he didn't feel worry about it 2 sin x 3 e 1 e .ln x I dx x = ∫ 2 sin x 3 e 1 e .ln x I dx x = ∫ Oxi hóa 6 gam ancol đơn chức Y , sau phản ứng thu được 8,4 gam hỗn hợp gồm ancol dư, andehit và nước. phần trăm ancol bị oxi hóa là. A. 60% B. 75% C.80% D. 85%