2 số đó là 116 và 32

Đây là bài lớp 5 ,lớp 6 sao không làm đc

MOT HINH CHU NHAT CO CHIEU DAILA 40CM CHIEU RONG LA1 PHAN TAM TINH CHU VI  VA DIEN H CUA HINH CHU NHAT DO

M = 2 + 2² + 2³ + ... + 2²⁰

Đầu tiên tính M đã hem

2M = 2 ( 2 + 2² + 2³ +.... + 2²⁰ )

2M = 2² + 2³ + 2⁴ + ... + 2²¹

2M - M = ( dòng 2M ngay trên ) - ( đầu bài )    

M = 2²¹ - 2 

M = 2²⁰ . 2 - 2

M = (2⁴)⁵ . 2 - 2 ( vào năm sẽ bít )

M = ( ... 6 ) . 2 - 2

M = (...2) - 2 

M = ...0 chia hết cho 5 

Học tốt

\(M=2+2^2+2^3+...+2^{20}\)

\(=\left(2+2^2+2^3+2^4\right)+...+\left(2^{17}+2^{18}+2^{19}+2^{20}\right)\)

\(=2\left(1+2+2^2+2^3\right)+...+2^{17}\left(1+2+2^2+2^3\right)\)

\(=2.15+...+2^{17}.15\)

\(=15\left(2+2^5+...+2^{17}\right)⋮5\)

a, tia gốc A : Ax ; AB ; AC ; Ay

  tia gốc B : BA ; Bx ; BC ; By

 tia gốc C : Cy ; CB ;CA ; Cx

b) 2tia đối nhau gốc B là : BA và BC

c) Điểm B nằm giữa 2 điểm còn lại vì BA và BC đối nhau \(\Rightarrow\)B nằm giữa !

Ta có: A=1/21 + 1/22 + 1/23 + ... + 1/60

           A= (1/21 + 1/22 + ... + 1/40) + (1/41 + 1/42 + ... + 1/60)

           A < 1/20 * 20 + 1/40 * 20 = 1 + 1/2 = 3/2 

Lại có: A = (1/21 + 1/22 + ... +1/40) + (1/41+ 1/42 + ... +1/60) 

           A > 1/40*20 + 1/60 * 20 = 1/2 + 1/3 = 5/6 > 11/15

==> 11/15 < 1/21 + 1/22 + ... + 1/60 < 3/2

Ta có: A=1/21 + 1/22 + 1/23 + ... + 1/60

           A= (1/21 + 1/22 + ... + 1/40) + (1/41 + 1/42 + ... + 1/60)

           A < 1/20 * 20 + 1/40 * 20 = 1 + 1/2 = 3/2 

Lại có: A = (1/21 + 1/22 + ... +1/40) + (1/41+ 1/42 + ... +1/60) 

           A > 1/40*20 + 1/60 * 20 = 1/2 + 1/3 = 5/6 > 11/15

==> 11/15 < 1/21 + 1/22 + ... + 1/60 < 3/2

nhung van chua chac vi lay bua ra ma dap thu xem no co vo ko

nước nha

Đó là biển.

Là Biển ak

Xét 1m³ rượu ở 0°C thì có khối lượng 800kg

Vậy thể tích ở 30°C là:

\(V=V_0+\frac{1}{1000}V_0\)\(.t=1+\frac{1}{1000}.30=1,03m^3\)

Khối lượng riêng của rượu ở 30°C là: 

\(D=\frac{m}{V}=\frac{800}{1,03}\approx777kg\text{/}m^3\)

My dream house is not necessarily a large house, as long as it fits my style and character. It is located on the outskirts of town. It will be a two- storey house facing west-south side. Moreover, my house can not be lack of a large garden surrounded by thousands of different colors of flowers and fruits. I it the most when having a breakfast or enjoying night views in my own garden. Simplicity is beauty, this explains why I would prefer an airy space rather than a well-equipped house. However, the house should have basic necessities in the kitchen and bathroom to serve all my demands in daily life. In addition, I will use bright color tones for the whole house, especially my bedroom to make it more spacious. My bedroom will be more perfect and ideal if it has a balcony where i could smell the fragrance from the garden as well as enjoy the sound of the birds in the morning. Besides, I also have an intention of having a small garage and storage. In conclusion, I wish I could make my dream become true.

I wish I would have a big penthouse in a big city. It will be a modern and comfortable near my working place. My house has two floors with 3 bedrooms, a living room, a kitchen and an entertainment room. All equipment in my house will be high-tech to serve my daily life in the best way. In my bedroom, it will painted a bright color tone to make a room more spacious. I will hang on the wall a few beautiful paintings and photos. There is a dressing room where I display my collection clothes and shoes. An entertainment room will be well-equipped with a smart TV and a modern karaoke system. Especially, on the second floor, there will be a large balcony where my family set up a party and have a barbecue with our lovely friends at the weekends. My future house must be beautiful and I will make it become true.

I have my own room since I was in 4th grade, and I would love to return to my room after a long and tired day. At first my parents decorated my room in a very simple way; they painted the walls in a clean color of white and did not place much furniture in the room. A few years later when I was a little older, I started to pay more attention to it, and now it has become a place which has a lot of my personal signs. I paint the walls in light pink, and I hang some family photos so the walls are not too empty. The monotonous bed was renewed by me; I replaced the entire bed with a new outfit that featured my favorite cartoon characters such as Sailor Moon, Doraemon and Totoro. My bed is not too wide, but I still make room for a lot of stuffed animals and pillows. They are all my best friends, and I will not be able to sleep if one of them is not present. Next to the bed is a tall pink wardrobe, there is a mirror on the front door so I can look at myself every time I get dress. In the corner of the room is a pretty desk which my dad made for me. It is white, and it also has the bookcase as well as some drawers with lockers so that I can comfortably store my personal belongings. In addition to the wooden chair which I usually use to study, there are also several small couches in the room for me to seat on while reading books or listening to music. There are also a lot of nonsense things in my room, but basically this room has everything I need. This room is my own secret cave, and I will always preserve it in the best condition.

My favorite room in my house I would have to say it's my bedroom. The reason my bedroom is the my favorite room in my house, because it's the biggest room in my house. I have everything in my room my plat screen,my Ps3, and my surround sound. Obviously, when I want some alone time I go to my bedroom and be on my laptop or playing Black Ops.

I really don't being in my living room, because my twin sister and I fight for the T.V. So when I want to watch my favorite program I just go to my bedroom. I also my bedroom, because I have my own mini fridge and I put all my snacks in my mini fridge. My bedroom is the most soothing place in the whole house, because no one enters my bedroom.

That's the reasons why my bedroom is my most favorite spot in my bedroom. I also go in my bedroom to work on my homework and won't get disturbed. My room is a great place to be in I get the best internet access. So that's why my bedroom is my most favorite place in my house.