Trong không gian \(Oxyz\), phương trình mặt cầu \(\left( S \right)\) có tâm \(I\left( { - 1;2;1} \right)\) và đi qua điểm \(A\left( {0;4; - 1} \right)\) là
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
Mặt cầu đi qua điểm $A(0;4;-1)$, vậy bán kính $R = IA = \sqrt{(0-(-1))^2 + (4-2)^2 + (-1-1)^2} = \sqrt{1+4+4} = \sqrt{9} = 3$.
Phương trình mặt cầu là $(x+1)^2 + (y-2)^2 + (z-1)^2 = R^2 = 3^2 = 9$.
Câu hỏi liên quan
Complete the sentence with the correct form of 'will' or 'be going to'.
A: Why is she wearing her best dress?
Read the following passage about green living habits 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 an era marked by climate change and environmental degradation, adopting green living habits has become increasingly vital. Green living refers to a lifestyle that seeks to minimize one’s ecological footprint through conscious choices in daily activities. This can include everything from reducing waste to conserving energy and using sustainable products. As more individuals recognize the importance of preserving our planet, the movement toward greener practices continues to gain momentum.
One of the most significant aspects of green living is its focus on sustainability. By choosing products that are eco-friendly, consumers can support businesses that prioritize environmental responsibility. For instance, using reusable bags, bottles, and containers reduces plastic waste and promotes a circular economy. Furthermore, opting for locally sourced foods not only supports local farmers but also decreases the carbon emissions associated with transportation.
When green living habits are adopted, they can lead to profound changes in our environment. By reducing their energy consumption through the use of energy-efficient appliances, individuals help lower greenhouse gas emissions. Consequently, this contributes to cleaner air and mitigates the effects of climate change. Moreover, by practicing water conservation methods, such as fixing leaks and using low-flow fixtures, households can significantly decrease water waste, promoting the sustainable use of this precious resource.
In conclusion, educating individuals about green living habits is crucial for promoting a more sustainable future. Schools and community organizations can offer workshops and resources that highlight the benefits of eco-friendly practices. Additionally, social media campaigns can raise awareness and encourage people to share their experiences with sustainable living. By empowering individuals to make informed choices, we can collectively work toward a healthier planet for generations to come.
The word ‘vital’ in paragraph 1 is OPPOSITE in meaning to ______.
Một bánh xe có bán kính là R = 10,0 ± 0,5 cm. Sai số tương đối của chu vi bánh xe là:
- Đơn vị của từ thông là
Kí hiệu nguyên tử nào sau đây được viết đúng?
Read the passage and do the tasks below. Choose the best answers to complete the following sentences.
Most people relate stress to physical symptoms like an upset stomach or headaches. Research has suggested that negative emotions and thoughts may also have close links to our brain. Researchers have started finding out why we tend to remember negative things more strongly and, in more detail, than good ones. “The hrain handles positive and negative information in different parts. Negative emotions involve more thinking, and the information is processed more thoroughly. Thus, we tend to ruminate more about unpleasant events and use stronger words to describe them than happy ones," said Clifford Nass, a professor at Stanford University.
Rick Hanson also shares the idea that our minds naturally focus on the bad and discard the good. He stated, "negative stimuli produce more neural activity than do equally intense positive ones. They are also perceived more easily and quickly." This was obtained from his little experiment in which twenty people were asked to look at pictures showing anger or happiness. The participants could identify angry faces faster than happy ones even if it was so quickly.
In a journal article Baumeister co-authored in 2001, "Bad is Stronger Than Good", he concluded, "bad emotions, bad parents and bad feedback have more impact than good ones." This is "a basic and wide-ranging principle of psychology". Thus, Baumeister and his colleagues noted that bad incidents, such as losing your dreamy job and breaking up with your girlfriend or boyfriend, may have a greater impact than landing a job or receiving a marriage proposal.
People have generally related stress to ____.
Choose a suitable word or phrase (marked A, B, C or D) to fill in each blank.
Tam Chuc Pagoda is _________ tourist attraction in Ha Nam; hundreds of thousands of tourists flock to this area every year.
Nếu một doanh nghiệp sản xuất \(x\) sản phẩm trong một tháng \(\left( x\in {{\mathbb{N}}^{\text{*}}};1\le x\le 4500 \right)\) thì doanh thu nhận được khi bán hết số sản phẩm đó là \(F\left( x \right)=-0,01{{x}^{2}}+400x\) (nghìn đồng), trong khi chi phí sản xuất bình quân cho mỗi sản phẩm là \(G\left( x \right)=\frac{30000}{x}+270\) (nghìn đồng). Giả sử số sản phẩm sản xuất ra luôn được bán hết. Trong một tháng, doanh nghiệp đó cần sản xuất ít nhất bao nhiêu sản phẩm để lợi nhuận thu được lớn hơn 100 triệu đồng?
Có nhiều nguyên nhân dẫn đến tình trạng lạm phát, ngoại trừ nguyên nhân nào sau đây?
Hiến pháp năm 2013 đã quy định công dân có các nghĩa vụ cơ bản nào sau đây?
Read the passage below and choose A, B, C or D.
Millions of people are using cellphones today. In many places, it is actually considered unusual not to use one. In many countries, cellphones are very popular with young people. They find that the phones are more than a means of communication - having a mobile phone shows that they are cool and connected.
The explosion in mobile phone use around the world has made some health professionals worried. Some doctors are concerned that in the future many people may suffer health problems from the use of mobile phones. In England, there has been a serious debate about this issue. Mobile phone companies are worried about the negative publicity of such ideas. They say that there is no proof that mobile phones are bad for your health.
On the other hand, medical studies have shown changes in the brain cells of some people who use mobile phones. Signs of change in the tissues of the brain and head can be detected with modern scanning equipment. In one case, a traveling salesman had to retire at young age because of serious memory loss. He couldn't remember even simple tasks. He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day, every day of his working week, for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't agree.
What is it that makes mobile phones potentially harmful? The answer is radiation. High-tech machines can detect very small amounts of radiation from mobile phones. Mobile phone companies agree that there is some radiation, but they say the amount is too small to worry about.
As the discussion about their safety continues, it appears that it's best to use mobile phones less often. Use your regular phone if you want to talk for a long time. Use your mobile phone only when you really need it. Mobile phones can be very useful and convenient, especially in emergencies. In the future, mobile phones may have a warning label that says they are bad for your health. So for now, it's wise not to use your mobile phone too often.
What is mentioned about the man who used his cellphone too often in paragraph 3?
Nội dung có đề mục "Tìm thêm sự trợ giúp" trong tài liệu hướng dẫn đem lại thông tin nào sau đây?
Trong Truyện An Dương Vương và Mị Châu - Trọng Thuỷ, chi tiết nào KHÔNG nói lên sự mất cảnh giác và thái độ cả tin, ngây thơ của Mị Châu trong tình yêu?
Ưu điểm của trồng trọt công nghệ cao:
Cho khối hộp chữ nhật ABCD.A'B'C'D' có \(AA' = a\), \(AB = a\), \(AD = a \sqrt{2}\). Góc giữa đường thẳng A'C và mặt phẳng \((ABCD)\) bằng bao nhiêu?
Nhận định nào sau đây không đúng với vai trò của hô hấp?
Đâu không phải là một hoạt động của nền kinh tế nước ta?
Trong những kí hiệu được đánh số thứ tự (1), (2), (3), (4), (5) như hình bên dưới, tên gọi của các linh kiện theo đúng thứ tự lần lượt là
Cho biết nguyên tử khối của các nguyên tố: H = 1; C = 12; O = 16; N = 14; Na = 23; Al = 27; Fe = 56.
PHẦN I. Câu trắc nghiệm nhiều phương án lựa chọn. Thí sinh trả lời từ câu 1 đến câu 18. Mỗi câu hỏi thí sinh chỉ chọn một phương án.
Câu 1. Kết quả phân tích nguyên tố trong phân tử một peptide X như sau: %C = 41,10%; %H = 6,85%; %N = 19,18% (về khối lượng); còn lại là oxygen. Từ phổ khối lượng, xác định được phân tử khối của X bằng 146. Phát biểu nào sau đây là đúng?
Read of the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.
Colors of Humanity: Experience the World in One Place
Join our amazing cultural festival!
One culture might showcase exuberant, saturated colors in its artistic traditions, while (7)_________ artistic traditions cultivate an appreciation for more restrained, gentle chromatic expressions. Our festival (8)_________ cultures from around the world.
The (9)_________ on children's faces makes our event special. (10)_________ language differences, people connect through art.
The beauty of traditional (11)_________ attracts many visitors. A (12)_________ of food from different countries will be available to try.
Festival Details:
Date: June 15-17, 2025
Location: City Park
Free entry for children
Food and craft markets
Music and dance shows every hour
Contact: worldcolors@example.com | 555-0123