Thirteen questions on 37 pages of Mathematics

Thirteen questions on 37 pages of Mathematics

It is suggested that the questions should be sent in the future, otherwise it is impossible for you to get answers

The answer to the 18th question

Human life is limited. But why do many people not cherish life? Is it because of setbacks and pain in life? Life and life are closely related. Without life, there will be no life, without life, there will be no happiness. If you want to succeed, you must cherish life
Life can give people a lot of things. But it depends on our consciousness and attitude towards life. Setbacks and pain in life can't eliminate our consciousness and attitude towards life. As long as we keep working hard in our limited life, we don't need to curse our life. Success and failure are just a matter of thinking. If we fail, we start all over again. Success doesn't need to be proud, Success means that we have gained the best from our efforts. We need not be discouraged if we fail. Failure at least gives us experience. If we fail, we will succeed one day
Solzhenitsyn once said: "the person who lives the longest is not the one who lives the most time." as long as we make good use of time and make life meaningful and valuable, our life will be long. We should not easily give up life. Life is beautiful, and the value and value of life are our own problems. Life is given only once, and people can only live once in the world, We should not let our life be mediocre. We can do a lot of helpful things in our limited time
Marille also said: "a good man's life is twice that of others, because he keeps his life in other people's memory." yes, those heroes who died in the Anti Japanese War, their lives are not so short, but long. They will live in this world forever. They have lived for centuries, and they will live in this world forever, People living in this world will never forget their limited life, we can also become infinite life
As long as we cherish life, we can get what we want. As long as we don't waste our lives, such lives are meaningful to us. Such lives are also long-term
In our limited life, we have a lot of disappointments, but this is also a setback in our life. The setback will only teach us and will not let us lose our way in the hazy life. We should look at every problem from an optimistic perspective. The setback and pain will only lead us to the bright road, Let's take a boat over Jiangzhu to seek the so-called happiness. In the vast Chinese history, we have never forgotten the existence of happiness. Let life bring us happiness!
Please cherish your life and pay attention to the bright future

Synonyms and antonyms of stormy waves

It's rough, but it's calm

There is a cylinder with a height of 10 cm and a surface area of 288 π square centimeter

Let the radius be r
2×π×r²+2×π×r×10=288π
2πr²+20πr=288π
r²+10r=144
r²+10r-144=0
（r+18）（r-8）=0
R = - 18 (rounding off) or r = 8
So:
volume
=π×8²×10
=640 π (CC)

How many years has the earth lived? How many years does the earth have in the end?

The earth's current life span is 4.6 billion years. As for how long the earth will exist in the future, it is still unknown. Here are the reference materials

The chemical equation is 2h2o2 = 2H2O + O2. There is a bottle of hydrogen peroxide that has not been used. The label on the bottle says: the mass fraction of H2O2 is 30%, the mass of the inner solution is 1000g, and the actual mass of this bottle of hydrogen peroxide is 920g
Q: what is the mass of decomposed H2O2 in this bottle?
Q: what is the mass fraction of H2O2 in the remaining hydrogen peroxide? (the calculation results are kept in integer.)
2. In order to solve the problem of oxygen absorption of fish, calcium peroxide (Cao 2) is added into water, which reacts with water to produce calcium hydroxide and oxygen. One enthusiast said that he took 2G of calcium peroxide sample into enough water to produce 224ml of oxygen (oxygen density is 1.43g / L). Q: the mass fraction of calcium peroxide in calcium peroxide sample

1.(1)mO2=1000-920=80g
2H2O2→2H2O+O2↑
Mh2o2 (decomposition) = 170g
(2) Mh202 (residual) = 1000 × 30% - 170 = 130g
c%=[130÷(1000-80)]×100%≈14.13%
2.mO2=0.224×1.43≈0.32g
n02=0.01mol
2CaO2+2H20→2Ca(OH)2+O2↑
nCaO2=0.02mol
mCaO2=1.44g
cCaO2%=(1.44÷2)×100%=72%

There are two squares, one big and the other small, whose perimeter differs by 20 cm and area by 55 square cm. What is the area of a small square?

55-5 × 5 = 30 (square centimeter); 30 ／ 2 ／ 5 = 3 (centimeter); 3 × 3 = 9 (square centimeter). Answer: the area of a small square is 9 square centimeter

Calculation 12 + 16 + 112 + 120 + 130 + 142=______ ．

12 + 16 + 112 + 120 + 130 + 142 = (1 − 12) + (12 − 13) + (13 − 14) + (14 − 15) + (15 − 16) + (16 − 17), = 1 − 17, = 67

Prove that cos @ divided by 1-sin @ equals 1 + sin @ divided by cos@
It is known that sin @ = change sign 2 divided by 2, and 2 & # 8364; [0.2 force] find the angle @ respectively

Remember to give the compensation points,

In the figure below, the side length of large square is 3cm, and that of small square is 2cm

According to the data in the question stem, we can get: (2 + 3) × 2 △ 2 + 3 × 3 △ 2 - (3 + 2) × 2 △ 2, = 5 × 2 △ 2 + 4.5-5 × 2 △ 2, = 5 + 4.5-5, = 4.5 (square centimeter), answer: the area of shadow part is 4.5 square centimeter