Trong các mệnh đề dưới đây, mệnh đề nào đúng?
\(\forall x \in \mathbb{R},{x^2} > 4 \Rightarrow x > - 2\).
\(\forall x \in \mathbb{R},{x^2} > 4 \Rightarrow x > 2\).
\(\forall x \in \mathbb{R},x > - 2 \Rightarrow {x^2} > 4\).
\(\forall x \in \mathbb{R},x > 2 \Rightarrow {x^2} > 4\)
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Mệnh đề “\(\forall x \in \mathbb{R},{x^2} > 4 \Rightarrow x > - 2\)” sai, chẳng hạn \(x = - 3\) thì \({x^2} > 4\) nhưng \(x < - 2\)
Mệnh đề “\(\forall x \in \mathbb{R},{x^2} > 4 \Rightarrow x > 2\)” sai, chẳng hạn \(x = - 3\) thì \({x^2} > 4\) nhưng \(x < 2\)
Mệnh đề “\(\forall x \in \mathbb{R},x > - 2 \Rightarrow {x^2} > 4\)” sai, chẳng hạn \(x = 0 > - 2\) nhưng \({x^2} < 4\)
Mệnh đề “\(\forall x \in \mathbb{R},x > 2 \Rightarrow {x^2} > 4\)” đúng
Chọn D.
Bộ Đề Kiểm Tra Giữa Học Kì I - Toán 10 - (Năm 2023 - 2024) - Các Trường THPT Trên Toàn Quốc là tài liệu giúp học sinh hệ thống lại các kiến thức đã học thông qua các câu hỏi ngắn gọn và súc tích. Các bài tập được thiết kế phù hợp với nhiều đối tượng học sinh, từ cơ bản đến nâng cao.
Câu hỏi liên quan
Read the following passage about managing change and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.
Growing up in Athens, Greece, Lydia Borsi remembers feeling tested when she tried to deal with mental health issues. Borsi says she had been seeing a therapist for anxiety. But she notes that people in Greece do not openly discuss mental health issues, which also get little attention in general healthcare services. “It was a lot more secretive. And people thought that I was a lot more unique,” Borsi said.
That all changed in 2017 when she moved to the United States to study at the University of Rochester in Rochester, New York. “When I came here, I really liked that people were not afraid to speak up about mental health and say that it’s important,” she said. The university was very supportive of her needs and offered plenty of information. She also became involved with a school group called Active Minds that helps students deal with mental health issues. [A]
Then due to the spread of the novel coronavirus, the University of Rochester had to move all its classes and some of its mental health resources online. Luckily, Borsi was able to connect with a mental health expert outside the school, in the local community. [B]
But as many of her American friends returned home, Borsi was stuck. Greece had succeeded in limiting the spread of the virus within its borders, but flights there from the U.S. are barred until July. Also, the health crisis has put her plans to seek admission to medical school in Britain on hold. [C] And she is not alone.
[D] In April, Active Minds launched a survey of over 2,000 students at U.S. colleges and universities. The study found that over 80 percent of those asked said the coronavirus crisis had negatively affected their mental health. One in five said it has affected them severely.
Laura Horne, chief program officer at Active Minds, says the findings are especially troubling given that the crisis is only going to make it harder for colleges and universities to help these students. “Colleges and universities had to pivot rather quickly to respond to COVID-19 and figure out all facets of university life, including mental health services. Now they have to figure out how to communicate with students,” Horne said.
Frank Chen is a Houston, Texas-based psychiatrist who has worked with college-age young adults. He points out that individuals at that age are in an important stage of their mental development. And college can be a difficult experience for students with or without mental health issues, as they balance work, studies, and personal relationships. Adding a major world event, like the spread of the coronavirus, makes it very difficult to predict what the long-term psychological effects might be. “I don’t think that there’s another event in the history of the people who are alive now that can really measure up to this,” said Chen.
The word ‘barred’ in paragraph 4 is closest in meaning to
Chọn ý đúng: Nhân tố quan trọng nhất góp phần mở rộng thị trường của hoạt động ngoại thương ở các nước trên thế giới hiện nay?
Phương trình \({\log _3}\left( {{x^2} - 3x - 5} \right) = {\log _3}x\) có bao nhiêu nghiệm?
Trong trường hợp dưới đây, chị C đóng vai trò là chủ thể gì của nền kinh tế?
"Chị C là nội trợ thường xuyên đi siêu thị để mua thực phẩm và các đồ gia dụng trong nhà".
Nhóm thực vật C3 được phân bố ra sao?
Chọn từ/cụm từ thích hợp vào chỗ … để hoàn thành phát biểu sau: “Mọi sinh vật sống đều được cấu tạo từ …, các hoạt động sống của cơ thể đều diễn ra trong …”.
Người bị lộ thông tin cá nhân đối mặt với rủi ro về bảo mật và quyền riêng tư, NGOẠI TRỪ điều nào sau đây?
Read the following advertisement/school announcement and mark the letter A, B, C, or D on your answer sheet to indicate the correct option that best fits each of the numbered blanks from 10 to 15.
ANNOUNCEMENT OF SCHOOL YEAR-END PARTY
- The School Youth Union would like to announce:
+ All students (13) _______ to be present at 19:00 on May 29.
+ Each class is to prepare a performance for the Talent Show. Each performance should not exceed 5 minutes.
+ Each class is to (14) _______ one student to take part in the “King and Queen of the Night” event.
- (15) _______ you have any questions, please contact your class monitor.
Read the passage carefully.
1. It is estimated that about 40 per cent of the world's population use social media, and many of these billions of social media users look up to influencers to help them decide what to buy and what trends to follow. An influencer is a person who can influence the decisions of his or her followers because of his or her knowledge or special knowledge in a particular area, e.g. fashion, travel, or technology. Influencers are now seen by many companies as a direct way to customers' hearts. Brands are now asking powerful influencers to market their products. With some influencers charging up to $25,000 for one social media post, it is no surprise that more and more people are keen to become influencers, too. If you are one of them, then here are five tips on how to do it.
2. Choose your niche: What is the area that you know most about? What do you feel most excited talking about? Find the specific area that you are most interested in and develop it.
3. Choose your medium and write an interesting bio: Most influencers these days are bloggers and micro-bloggers. Decide which medium – such as your own online blog, Instagram or Snapchat – is the best way to connect with your followers and chat about your niche area. When you have done that, write an attention-grabbing bio that describes you and your speciality area in an interesting and unique way. Make sure that people who read your bio will want to follow you.
4. Post regularly and consistently: Many influencers post daily on their social media accounts. The more you post, the more likely people will follow you. Also, make sure that your posts are consistent and possibly follow a theme.
5. Tell an interesting story: Whether it is a photo or a comment that you are posting, use it to tell a story that will catch the attention of your followers and help them connectwith you.
6. Make sure people can easily find your content: Publicize your posts on a variety of social media by hashtags and catchy titles to make sure that they can be easily found. There is no point writing the most exciting blogposts or posting the most attractive photographs if no one is going to see them.
7. Most importantly, if you want to become a social media influencer, you need to have patience. Keep posting and your following will gradually increase. Good luck!
Choose an option (A, B, C, or D) that best answers each question.
What can be inferred from paragraph 3?
Chức năng nào bên dưới phù hợp với thiết bị số thông minh?
Read the following passage about Building Understanding Across Nations and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.
In our interconnected world, cultural ambassadors play a vital role in bridging the gaps between different nations and peoples. These dedicated individuals and groups serve as links between cultures, fostering mutual understanding and respect through various activities and programs. Their mission is to showcase their own cultural heritage while learning about and appreciating others, creating pathways for meaningful dialogue and lasting connections across borders.
Cultural ambassadors employ numerous methods to achieve their goals. They organize traditional festivals and art exhibitions that display unique customs, allowing visitors to experience different cultures firsthand. Language exchange programs enable people to communicate more effectively, while cultural workshops teach traditional crafts, music, and dance. These ambassadors also utilize digital platforms to reach wider audiences, sharing stories and traditions through social media and online events that connect people from different corners of the world.
Despite their important work, cultural ambassadors face several challenges in their mission. Stereotypes and prejudices can create barriers to understanding, while language differences sometimes lead to misunderstandings. Limited resources and funding may restrict their activities, and political tensions between nations can complicate their efforts. However, these dedicated individuals persist in their work, believing that personal connections and shared experiences can overcome these obstacles and promote harmony among different communities.
Looking ahead, the role of cultural ambassadors becomes increasingly significant in our global society. Their efforts to build bridges between nations contribute to reducing conflicts and fostering peace. Through their continued dedication to promoting cross-cultural understanding, these ambassadors help create a more inclusive and connected world where differences are celebrated rather than feared. This ongoing process of cultural exchange remains essential for building a future based on mutual respect and cooperation.
The word “their” in paragraph 2 refers to _________.
Choose one word whose underlined part is pronounced differently:
Cho tứ diện ABCD có độ dài các cạnh \(A B=A C=A D=B C=B D=a\) và \(C D=a \sqrt{2}\). Tính góc giữa hai đường thẳng AD và BC.
Hoạt động tạo ra sản phẩm vật chất và tinh thần quyết định tạo ra sản phẩm vật chất và tinh thần quyết định sự tồn tại phát triển của con người và xã hội gọi là gì?
Di sản phi vật thể có nguy cơ bị mai một vì lí do nào sau đây?
Trường hợp dưới đây, loại hình thất nghiệp nào đã được đề cập đến?
"Do kinh tế thế giới suy thoái đã làm cho các doanh nghiệp trong nước, nhất là các doanh nghiệp nhỏ gặp nhiều khó khăn. Nhiều doanh nghiệp phải đóng cửa, tạm ngừng sản xuất kinh doanh. Hệ quả là người lao động trong những doanh nghiệp này bị thất nghiệp".
Những ai trong trường hợp dưới đây đã không vi phạm quy định của pháp luật về quyền bình đẳng giữa các dân tộc trên phương diện kinh tế?
Trường hợp. Để mở rộng sản xuất, Công ty X đăng tin tuyển dụng 3 kĩ sư tin học biết tiếng Anh vào làm việc. Đối chiếu với các tiêu chuẩn mà công ty đề ra đối với ứng viên, anh Q và chị M thấy mình đều đủ cả nên đã đăng kí dự tuyển. Tuy nhiên, hồ sơ của anh Q không được anh P (Giám đốc Công ty X) chấp nhận vì lí do anh Q là người dân tộc thiểu số.
Bước 1 của quy trình thiết kế kĩ thuật là:
Read the following passage about human life expectancy and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.
In the UK, comprising England, Scotland, Wales, and Northern Ireland, jokes and tricks can be played until noon on 1 April. After midday it's considered bad luck to play a trick. Anyone who forgets this and tries a joke in the afternoon becomes an 'April Fool' themselves.
So, what kind of jokes do people play? Well, a simple example would be telling your friend that their shoelaces are undone. Then, when they bend down to do them up, you shout, 'April Fool!', and they realise their shoelaces are fine.
Maybe it's not your kind of humour, but watch out, there's always someone who will find it funny! In Ireland, a popular prank is to send someone on a 'fool's errand'. The victim is sent to deliver a letter, supposedly asking for help. When the person receives the letter, they open it, read it and tell the poor messenger that they will have to take the letter to another person. This continues and the victim ends up taking the message to several different people until someone feels sorry for them and shows them what the letter says: 'Send the fool to someone else.'
In France, Belgium, the Netherlands (or Holland), Italy and French-speaking areas of Canada and Switzerland, the 1 April tradition is known as the “April Fish”. A common joke is to try to stick a paper fish onto a victim's back without being noticed.
Which country is NOT mentioned in the text?
- Dùng thông tin sau đâyy cho Câu 37 và Câu 38: Ba dây dẫn dài song song theo thứ tự lần lượt là 1,2 và 3. Các dây dẫn này ở trong cùng một mặt phẳng, cách đều nhau 10 cm. Dòng điện trong mỗi dây có cường độ 20 A và cùng chiều. Biết độ lớn cảm ứng từ do một dây dẫn thẳng dài mang dòng điện I tạo ra ở vị trí cách trục dây dẫn một khoảng r là \(B = 2,{0.10^{ - 7}}\left( {\frac{I}{r}} \right),\) với B tính bằng tesla (T), r tính bằng mét (m) và I tính bằng ampe (A).
Độ lớn của hợp lực do dây 1 và dây 2 tác dụng lên một mét dây 3 là bao nhiêu miliniutơn?