2) cho △ABC ⊥A, đường cao AH. gọi D, E lần lượt là 

hình chiếu của H tên AB, AC. c/m: A, D, H, E cùng thuộc 

1 đường tròn  

giúp mk vs ạ mk cần gấp

1) cho △ABC, đường cao BD, CE cắt nhau tại H

a) c/m: A, D, H, E cùng thuộc 1 đường tròn

b) c/m: B, D, E, C cùng thuộc 1 đường tròn

giúp mk vs ạ mk cần gấp

BT câu hỏi đuôi 3:

1. She is collecting stickers,...........?

2. We often watch TV in the afternoon,...........?

3. You have cleaned your bike,............?

4. John ang Max don't like maths,............?

5. Peter played handball yesterday,............?

6. They are going home from school,............?

7. Mary didn't do her homework last monday,...........?

8. He could have bought a new car,.............?

9. Kevin will come tonight,............?

10. I'm clever,...........?

giúp mk vs ạ mk cần gấp

BT câu hỏi đuôi 2:

1. He's been to Taxes,............?

2. Dogs like meat,................?

3. There are some apples left,...........?

4. I'm late,..............?

5. Let's go,..........?

6. Don't smoke,............?

7. He doesn't sing in the bathroom,.............?

8. He'll never know,.............?

9. I think he's from India,..............?

10. Lovely day today, ..............?

giúp mk vs ạ mk cần gấp

BT câu hỏi đuôi 1:

1. He sometimes reads the newspaper, .........?

2. You are Indian,........?

3. They had a nice weekend,...........?

4. Peggy didn't use the pencil,.........?

5. Mary has answered the teacher's question,............?

6. The boy is from Turkey,.........?

7. Sue wasn't listening,............?

8. Andrew isn't sleeping,.........?

9. Tom and Maria will arrive at Heathrow,...........?

10. She has a brother,...........?

giúp mkk vs ạ mk cần gấp

1) cho △ABC, đường cao BD, CE cắt nhau tại H

a) c/m: A, D, H, E cùng thuộc 1 đường tròn

b) c/m: B, D, E, C cùng thuộc 1 đường tròn

giúp mk vs ạ mk cần gấp

1) cho \(x>0\). CMR: \(x+\dfrac{1}{x}\ge2\) 

2) cho a, b, c, d>0. thỏa mãn \(a.b.c.d=1\). CM:

a) \(ab+cd\ge2\)

b) \(a^2+b^2+c^2+d^2\ge4\)

giúp mk vs ạ mk cần gấp