Với giá trị x∈R nào dưới đây thì mệnh đề chứa biến P(x): "x+1<x2" đúng?
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
- Với $x = \dfrac{1}{2}$, ta có $\dfrac{1}{2} + 1 < (\dfrac{1}{2})^2 \Leftrightarrow \dfrac{3}{2} < \dfrac{1}{4}$ (sai).
- Với $x = 1$, ta có $1 + 1 < 1^2 \Leftrightarrow 2 < 1$ (sai).
- Với $x = 2$, ta có $2 + 1 < 2^2 \Leftrightarrow 3 < 4$ (đúng).
- Với $x = 0$, ta có $0 + 1 < 0^2 \Leftrightarrow 1 < 0$ (sai).
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How long will a baby born today live? 100 years? 120 years? Scientists are studying genes that could mean long life for us all.
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There are many scientific studies of communities where healthy old age is typical. These include places like Calabria in southern Italy and the island of Okinawa in Japan. In Calabria, the small village of Molochio has about 2,000 inhabitants. And of these, there are at least eight people over a hundred years old. When researchers ask people like this the secret of their long life, the answer is almost always about food and is almost always the same: ‘I eat a lot of fruit and vegetables.’ ‘I eat a little bit of everything.’ ‘I neither smoke nor drink.’
In the past, scientists looked at things such as diet and lifestyle for an explanation of long life, but these days they are also looking at genetics. Researcher Eric Topol says that there must be genes that explain why people are protected from the effects of aging process. The new research into long life did scrutinize groups of people who have a genetic connection. One interesting group lives in Ecuador. In one area of the country there are a number of people with the same genetic condition. It’s called Laron syndrome. These people don’t grow very tall – just over one metre. But Laron syndrome also give them protection against cancer and diabetes. As a result, they live longer than other people in their families. Meanwhile, on the Hawaiian island of Oahu, there’s another group of long-lived men, Japanese-Americans. They have a similar gene to the Laron syndrome group.
Back in Calabria, researchers constructed the family trees of the 100-year-old people. They looked at family information from the 19th century to today. It is concluded that there are genetic factors that give health benefits to the men. This is a surprising result because generally in Europe, women live longer than men. So what really makes people live longer? It seems likely that it is an interaction of genes, the environment and probably a third factor – luck.
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Parents of a Tokyo elementary school are up in arms at being asked to pay 730 dollars for their child's school uniform. A public elementary school in Tokyo's upmarket Ginza district has decided to adopt new school uniforms designed by the luxury Italian designer Armani. The bespoke uniforms, which include a hat and bag, are priced at over 80,000 (730 dollars) each. Parents are angry at the school's decision and are protesting at what they view as the exorbitant price for a uniform of an eight-year-old child. The school said it wanted a designer uniform that represented the rich area of Ginza. School officials visited top department stores and decided to ask the fashion brand Armani to design the uniform.
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ANNOUNCEMENT OF CARDIFF BIKE RACE
We are going to take part in the Cardiff Bike Race. Please notice some important details:
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Sự tương tác do các nhà nghiên cứu Hokkaido miêu tả bao gồm một hiện tượng lý thuyết gọi là hiệu ứng Hall điện yếu. Đây là một tương tác điện và từ trong những điều kiện cực đoan, nơi hai lực cơ bản của tự nhiên – các lực điện từ hoặc lực yếu – sáp nhập thành lực điện yếu. Đây là một khái niệm lý thuyết, được chờ đợi có thể ứng dụng vào các điều kiện năng lượng cực cao trong giai đoạn vũ trụ sớm hoặc trong những va chạm của máy gia tốc hạt.
(Theo Thanh Phương tổng hợp, Cái nhìn mới vào các tương tác neutrino, đăng trên Tạp chí tia sáng, ngày 18/09/2023)
Plasma được mô tả như thế nào trong bài viết?
Số nghiệm của phương trình trên đoạn \(\text{cos}x=\text{sin}x\) trên đoạn \(\left[ -\frac{2\pi }{3};\frac{5\pi }{3} \right]\) là