K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

19 tháng 5 2021

\(a-b=2\Leftrightarrow a=b+2\)

\(P=3a^2+b^2+8\\ P=3\left(b+2\right)^2+b^2+8\\ P=3b^2+12b+12+b^2+8\\ P=4b^2+12b+20\\ P=\left(4b^2+12b+9\right)+11\\ P=\left(2b+3\right)^2+11\ge11\forall a;b\)

Dấu "=" xảy ra \(\Leftrightarrow b=\dfrac{-3}{2}\)

Pmin = 11

a: Ta có: EC//AB

AB⊥CD

Do đó: EC⊥CD

=>ΔCED nội tiếp đường tròn đường kính CD

=>O là trung điểm của CD(Vì C,E,D cùng nằm trên đường tròn O)

=>E,O,D thẳng hàng

b: Xét (O) có

ΔAEB nội tiếp

AB là đường kính

DO đó: ΔAEB vuông tại E

Xét tứ giác AEBD có 

O là trung điểm của AB

O là trung điểm của ED

Do đó: AEBD là hình bình hành

mà \(\widehat{AEB}=90^0\)

nên AEBD là hình chữ nhật

NV
12 tháng 4 2021

\(A=\sqrt{2a\left(b+1\right)}+\sqrt{2b\left(c+1\right)}+\sqrt{2c\left(a+1\right)}\)

\(A=\dfrac{1}{\sqrt{2}}\sqrt{4a\left(b+1\right)}+\dfrac{1}{\sqrt{2}}\sqrt{4b\left(c+1\right)}+\dfrac{1}{\sqrt{2}}\sqrt{4c\left(a+1\right)}\)

\(A\le\dfrac{1}{2\sqrt{2}}\left(4a+b+1\right)+\dfrac{1}{2\sqrt{2}}\left(4b+c+1\right)+\dfrac{1}{2\sqrt{2}}\left(4c+a+1\right)\)

\(A\le\dfrac{1}{2\sqrt{2}}\left[5\left(a+b+c\right)+3\right]=2\sqrt{2}\)

\(A_{max}=2\sqrt{2}\) khi \(a=b=c=\dfrac{1}{3}\)

12 tháng 4 2021

em cảm ơn nhiều!

28 tháng 9 2023

a) \(\dfrac{A}{x-3}=\dfrac{y-x}{3-x}\left(Đk:x\ne3\right)\)

\(A=\dfrac{\left(x-3\right)\left(y-x\right)}{3-x}=x-y\)

b) \(\dfrac{5x}{x+1}=\dfrac{Ax\left(x-1\right)}{\left(1-x\right)\left(x+1\right)}\left(Đk:x\ne\pm1\right)\)

\(A=\dfrac{5x\left(1-x\right)\left(x+1\right)}{x\left(x-1\right)\left(x+1\right)}=-5\)

c) \(\dfrac{4x^2-5x+1}{A}=\dfrac{4x-1}{x+3}\left(Đk:x\ne-3;A\ne0\right)\)

\(A=\dfrac{\left(4x^2-5x+1\right)\left(x+3\right)}{4x-1}=\dfrac{\left(x-1\right)\left(4x-1\right)\left(x+3\right)}{4x-1}\)

    \(=\left(x-1\right)\left(x+3\right)=x^2+2x-3\)

29 tháng 9 2023

tv cũ comback hả?

Có ai giúp em bài này với ạ! EM CẢM ƠN Ạ!   jogging       photography       gardening        basketball       gymnastics  cycling        bird-watching         chess             dancing         ice skating1.__________             : a game played by two people on a square board, in which each player has 16 pieces thay can be moved on the board in different ways.2.__________             : the job or activity of working in a garden, growing and taking care of the plants, and keeping it...
Đọc tiếp

Có ai giúp em bài này với ạ! EM CẢM ƠN Ạ!

 

  jogging       photography       gardening        basketball       gymnastics

  cycling        bird-watching         chess             dancing         ice skating


1.__________             : a game played by two people on a square board, in which each player has 16 pieces thay can be moved on the board in different ways.

2.__________             : the job or activity of working in a garden, growing and taking care of the plants, and keeping it attractive.

3.__________             : a game played by two teams of five men or six women who score points by throwing a large ball through an open net hanging from a metal ring.

4.__________             : the sport or activity of riding a bicycle.

5.__________             : the art of moving your body to music.

6.__________             : moving across ice using special shoes with a thin metal bar fixed to the bottom that you wear to move quickly on ice.

7.__________             : the activity of running at a slow regular speed, especially as a form of exercise.

8.__________             : the hobby of studying wild birds in their natural environment.

9.__________             : the hobby of studying wild birds in their natural environment, physical exercises and activities performed inside, often using equipment such as bars and ropes which are intended to increase the body’s strength and the ability to move and bend easily.

10._________             : the activity or job of taking photographs or films.

2
25 tháng 9 2021

1. chess

2. gardening

3. basketball

4. cycling

5. dancing

6. ice skating

7. jogging

8. bird-watching

9. gymnastics

10. photography

25 tháng 9 2021

1._______chess___             : a game played by two people on a square board, in which each player has 16 pieces thay can be moved on the board in different ways.

2.____gardening______             : the job or activity of working in a garden, growing and taking care of the plants, and keeping it attractive.

3._____basketball_____             : a game played by two teams of five men or six women who score points by throwing a large ball through an open net hanging from a metal ring.

4._____cycling_____             : the sport or activity of riding a bicycle.

5.___dancing_______             : the art of moving your body to music.

6._ice skating_________             : moving across ice using special shoes with a thin metal bar fixed to the bottom that you wear to move quickly on ice.

7.____jogging______             : the activity of running at a slow regular speed, especially as a form of exercise.

8.__________             : the hobby of studying wild birds in their natural environment.

9.______bird-watching____             : the hobby of studying wild birds in their natural environment, physical exercises and activities performed inside, often using equipment such as bars and ropes which are intended to increase the body’s strength and the ability to move and bend easily.

10.___photography______             : the activity or job of taking photographs or films.

20 tháng 9 2021

1 A

2 D

3 A

4 C

5 C

6 A

7 A

8 B

9 D

10 A

11 D

12 D

13 C