Cho A = \(\frac{1}{4^2}\)+ \(\frac{1}{6^2}\)+\(\frac{1}{8^2}\)+ ... + \(\frac{1}{160^2}\) . Chứng minh \(\frac{1}{8}\)< A < \(\frac{3}{16}\).
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x.(2/3-3/4)=-11/6
x.-1/12=-11/6
x=-11/6:-1/12
x=-11/6.-1/2
x=11/72
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In the middle of the hustle and bustle of life, someone stopped and listened to the ocean's cry for help, saw the blood flowing from the fallen trees, felt the faint breath of mother earth. Nature is raising the message "Please protect the environment!".
The atmosphere we are breathing, the water we are using every day, the nature of mountains, rivers, houses, that's the environment. The environment is everything that surrounds us and has an important influence on the survival of mankind. "Environmental protection" is the action of every person to help our Earth more clean and healthy, helping people avoid the threat of nature.
The writer once said with the general idea that it takes 180 million years for the rose to bloom, 380 million years for the butterfly to fly, meaning that the environment in which we are living has to go through a long process of formation. and harsh. Yet, in recent years, what are people doing to the environment? A series of illegal deforestation, illegal burning, and unrelenting discharges Formosa Co., the world's domes waste amounting to 3.5 million tons per day, has caused pollution problems. soil and water pollution, especially climate change. The huge amount of indestructible plas bags has caused the greenhouse effect, causing many extreme weather phenomena such as earthquakes, tsunamis, and droughts. Most recently, Japan, a temperate country, experienced a record heat wave, while the United States was also suffering the heaviest storms in history. Environmental pollution not only blurs the landscape of each country, but also depresses the economy, culture and society, and promotes the rapid elimination of human life.
"People are born not to vanish a grain of unknown sand." Yes, in order not to vanish, we today and today will continue to build a healthy and sustainable environment. Throwing rubbish in a bin, planting a small tree, saying "no" to plas bags - these small actions have also helped to add a little green to our sphere of life. Every year, the United Nations organizes "Earth Day" events and receives responses from many countries around the world. From there, it also shows the correct awareness as well as people's interest in natural disasters. More and more non-profit organizations, enthusias young people dare to stand up to protect the wildlife, protect the pristine gardens - the common roof of all animals.
Our actions, big and small, are still holding on to life day by day. Protecting the environment is not a day-to-day process but the responsibility of every individual in this world, in every job, every breath and step that is crucial to the survival of the Earth. . Students can also contribute to this work by doing small but meaningful things: taking care of the greenery of the class house, disposing of trash in the right places or choosing a bus to move. The environment sometimes only requires love in such pracal activities, because it comes from the sense of responsibility and the sincerity of good people.
“This Earth is ours. The blue ball flies in the blue sky ... ”Let me and you let the ball fly in the vast universe with the green of peace, hope and freshness too!
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STT Tên cây thường gọi Nơi mọc Môi trường sống Đặc điểm hình thái của cây Nhóm thực vật
1. Tảo Nước Nước Chưa có rễ, thân, lá Bậc thấp
2. Rêu Ẩm ướt Ẩm ướt Rễ giả, thân lá nhỏ Bậc cao
3. Rau bợ Nước Nước Có rễ, thân, lá Bậc cao
4. Dương xỉ Cạn Cạn Sinh sản bằng bào tử Bậc cao
5. Thông Cạn Cạn Sinh sản bằng nón Bậc cao
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\(\frac{A}{3}=\frac{3}{20.23}+\frac{3}{23.26}+...+\frac{3}{77.80}\)
\(\frac{A}{3}=\frac{23-20}{20.23}+\frac{26-23}{23.26}+...+\frac{80-77}{77.80}\)
\(\frac{A}{3}=\frac{1}{20}-\frac{1}{23}+\frac{1}{23}-\frac{1}{26}+...+\frac{1}{77}-\frac{1}{80}=\frac{1}{20}-\frac{1}{80}=\frac{3}{80}\Rightarrow A=\frac{9}{80}< 1\)
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x O t y m 120º
a) Có: xOy và yOt là hai góc kề bù (gt)
=> xOy + yOt = 180º
<=> 120º + yOt = 180º
<=> yOt = 180º - 120º
<=> yOt = 60º
Vậy, yOt = 60º
b) +) Vì tia Om là tia phân giác của yOt (gt)
=> mOt = mOy = 1/2 yOt = 1/2 60º = 30º
+) Có: xOy + yOt = 180º (cmt)
<=> xOt = 180º
=> Ox và Ot là hai tia đối nhau
=> Om nằm giữa hai tia Ox và Ot
=> xOm + mOt = xOt
<=> xOm + 30º = 180º
<=> xOm = 180º - 30º
<=> xOm = 50º
Vậy, xOm = 50º
Khen ta đi ta ngồi gõ mất 15p lận đó UwU
Trả lời:
a) xoy và yoz kề bù nên :
xoy + yoz = 180
hay 120 + yoz =180
yoz=180-120=60
Vậy góc yoz = 60 độ
b)ot là phân giác của xoy
nên: xOt = tOy = xOy/2=120/2=60
mà tOy + yOz = zOt
hay: 60 + 60 = zOt
120 = zOt
Vậy góc zOt = 120 độ
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2,08=\(\frac{52}{25}\)
Hieu so phan bang nhau la :52-25=27
So lon la : 27:27.52=52
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Vì có tia chung gốc nên số góc tạo thành là:
\(\frac{x.\left(x-1\right)}{2}\)
Ta có: \(\frac{x.\left(x-1\right)}{2}=325\)
=> \(x.\left(x-1\right)=325.2\)
=> \(x.\left(x-1\right)=650\)
=> \(x.\left(x-1\right)=26.25\)
=> \(x=26\)
Vậy: \(x=26\)