Tam thức nào sau đây nhận giá trị âm với mọi x < 1
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
Xét đáp án A: f(x) = x2 – 5x + 6
Xét biểu thức f(x) = x2 – 5x + 6 có ∆ = 1 > 0, hai nghiệm phân biệt là x = 2 ; x = 3 và a = 1 > 0
Ta có bảng xét dấu
Dựa vào bảng xét dấu ta có tam thức f(x) = x2 – 5x + 6 nhận giá trị âm khi 2 < x < 3.
Vậy đáp án A sai.
Xét đáp án B: f(x) = x2 – 16
Xét biểu thức f(x) = x2 – 16 có ∆’ = 16 > 0, hai nghiệm phân biệt là x = 4 ; x = – 4 ; và a = 1 > 0. Ta có bảng xét dấu
Dựa vào bảng xét dấu ta có tam thức f(x) = x2 – 16 nhận giá trị âm khi – 4 < x < 4
Vậy đáp án B sai.
Xét đáp án C: f(x) = x2 + 2x + 3
Xét biểu thức f(x) = x2 + 2x + 3 = 0 có ∆ < 0 ⇔Phương trình vô nghiệm và a = 1 > 0
Ta có bảng xét dấu
Dựa vào bảng xét dấu ta có tam thức y = x2 – 2x + 3 nhận giá trị dương với mọi xℝ
Vậy đáp án C sai.
Xét đáp án D: y = – x2 + 5x – 4.
Xét biểu thức f(x) = – x2 + 5x – 4 = 0 có ∆ = 9 > 0, hai nhiệm phân biệt là x = 1, x = 4 và a = – 1 < 0
Ta có bảng xét dấu
Dựa vào bảng xét dấu ta có tam thức y = – x2 + 5x – 6 nhận giá trị âm khi x.
Vậy đáp án D đúng.
Bộ Đề Kiểm Tra Học Kì II - Toán 10 - (Năm học 2022 - 2023) - Các Trường THPT Trên Toàn Quốc là tài liệu hỗ trợ học sinh rèn luyện kiến thức thông qua các câu hỏi trắc nghiệm được thiết kế từ cơ bản đến nâng cao. Học sinh có thể tự kiểm tra và đánh giá năng lực của mình sau mỗi phần học.
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Trong một máy cấp nước nóng dùng điện, bộ phận làm nóng hoạt động như một điện trở có công suất định mức là 2,2 kW ở điện áp 220 V.
Cường độ dòng điện hiệu dụng là bao nhiêu ampe (làm tròn kết quả đến chữ số hàng đơn vị)?
Hệ thống Cooc-đi-e có đặc điểm như thế nào?
Nơi diễn ra hoạt động trao đổi, mua bán hàng hoá được gọi là gì?
Có 3 điểm nằm dọc theo trục Ox (có chiều từ A đến B) theo thứ tự là A, B và C. Cho AB = 200 m, BC = 300 m. Một người xuất phát từ A qua B đến C rồi quay lại B và dừng lại ở B. Hỏi quãng đường và độ lớn độ dịch chuyển của người này trong cả chuyến đi là bao nhiêu? Chọn gốc tọa độ tại A.
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 18 to 22.
The philosopher St. Augustine famously stated, "The world is a book, and those who do not travel read only a page." This notion aligns with the value of study-abroad programs, (18)_______ diverse cultures, languages, and perspectives. These programs are not merely about academic learning but are transformative journeys that often leave a profound impact on participants. Students describe these experiences as "rewarding" and even "life-changing," (19)________. Such programs not only enrich students academically but also prepare them to navigate a globalized world with empathy and understanding.
A significant advantage of studying abroad lies in its ability to enhance experiential learning. Unlike traditional classroom instruction, firsthand encounters—such as observing art in its original context or engaging with local communities—can deepen one's understanding of a subject. As one student observed after viewing Michelangelo's David, (20)_________. Such moments sharpen one's senses, cultivate a sensitivity to beauty and pain, and foster a deeper awareness of the interconnectedness of human experiences.
Moreover, studying abroad nurtures self-reflection, an essential aspect of personal growth. By documenting their experiences, students can analyze their values and beliefs (21)________. This reflective process not only enhances their capacity to adapt but also helps them better understand themselves and their aspirations. As educators recognize these multifaceted benefits, efforts continue to expand access to study-abroad opportunities, ensuring (22)________.
Cho các câu sau, số câu đúng là?
1) Sử dụng chương trình con sẽ làm chương trình dễ hiểu, dễ tìm lỗi hơn.
2) Hàm chỉ được gọi một lần duy nhất ở chương trình chính.
3) Hàm luôn trả một giá trị qua tên của hàm.
4) Python chỉ cho phép chương trình gọi một hàm xây dựng sẵn trong các thư viện của Python.
5) Khai báo hàm trong Python luôn có danh sách tham số.
Read thefollowing passage and mark the letter A, B, C or D on your answer sheet to indicate the option that bestfits each of the numbered blanksfrom 18 to 22.
Peer pressure, (18) ________, can have both positive and negative effects. For instance, when surrounded by motivated peers, (19) ________. Positive peer pressure can be a great motivator, as peers who excel in academics or extracurricular activities can inspire others to follow suit. However, peer pressure can also lead to negative outcomes. The influence of friends who engage in risky behaviors, such as skipping school or using substances, can encourage others to make poor decisions. Studies have shown that teenagers are more likely to take risks in the presence of their peers because they feel more confident when surrounded by others.
While peer pressure is often associated with negative behavior, (20) ________. For example, students may be encouraged to excel in their studies or participate in volunteer activities due to the positive influence of their peers. However, it is important to develop strong decision-making skills and self-confidence (21) ________.
Parents and educators play a key role in helping young people navigate peer pressure. By teaching young people how to recognize both positive and negative peer pressure, and how to make independent, thoughtful decisions, parents and educators can help ensure that students thrive in a healthy, supportive environment. Encouraging open communication, providing advice on how to stay true to one's values, and helping students develop self-confidence are all crucial aspects of this process.
In conclusion, peer pressure is a powerful influence. (22) ________, teenagers can succeed and grow in a positive social environment.
Read the passage below and choose A, B, C or D to answer each question from 641 to 645.
Cities develop as a result of functions that they can perform. Some functions result directly from the ingenuity of the citizenry, but most functions result from the needs of the local area and of the surrounding hinterland (the region that supplies goods to the city and to which the city furnishes services and other goods). Geographers often make a distinction between the situation and the site of a city. Situation refers to the general position in relation to the surrounding region, whereas site involves physical characteristics of the specific location. Situation is normally much more important to the continuing prosperity of a city. If a city is well situated in regard to its hinterland, its development is continuing prosperity of a city. If a city is well situated in regard to its hinterland, its development is much more likely to continue. Chicago, for example, possesses an almost unparalleled situation: it is located at the southern end of a huge lake that forces east-west transportation lines to be compressed into its vicinity, and at a meeting of significant land and water transport routes. It also overlooks what is one of the world’s finest large farming regions. These factors ensured that Chicago would become a great city regardless of the disadvantageous characteristics of the available site, such as being prone to flooding during thunderstorm activity.
Similarly, it can be argued that much of New York City’s importance stems from its early and continuing advantage of situation. Philadelphia and Boston both originated at about the same time as New York and shared New York’s location at the western end of one of the world’s most important oceanic trade routes, but only New York possesses an easy-access functional connection (the Hudson- Mohawk Lowland) to the vast Midwestern Hinterland. This account does not alone explain New York’s primacy, but it does include several important factors. Among the many aspects of situation that help to explain why some cities grow and others do not, original location on a navigable waterway seems particularly applicable. Of course, such characteristics as slope, drainage, power resources, river crossings, coastal shapes, and other physical characteristics help to determine city location, but such factors are normally more significant in early stages of city development than later.
What does the word “it” in paragraph 2 refer to?
Bạn Mai sử dụng dung dịch phân bón để bón qua lá cho cây cảnh trong vườn. Để bón phân hợp lí, bạn Mai cần thực hiện bao nhiêu chỉ dẫn sau đây?
I. Bón đúng liều lượng.
II. Không bón khi trời đang mưa.
III. Không bón khi trời nắng gắt.
IV. Bón phân phù hợp với thời kỳ sinh trưởng của cây.
Chế phẩm vi khuẩn trừ sâu hiệu quả với:
Read the following passage about the Designing Spaces That Connect Us to Nature 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.
Biophilic design has been turning heads and winning hearts by incorporating natural elements into our living and working spaces. This approach recognizes our innate connection to nature and how it affects our well-being. Studies show that exposure to natural light, plants, and natural materials can reduce stress and improve productivity. Many modern architects now integrate gardens, water features, and large windows into their designs. These elements help create environments where people can thrive both mentally and physically. As one designer put it, "We're bringing the outside in to help people feel at home in their skin."
The benefits of biophilic design extend beyond aesthetics. [I] Hospitals with views of nature report faster patient recovery times. Office buildings with natural elements see decreased absenteeism and increased worker satisfaction. [II] Schools incorporating biophilic principles observe improved student concentration and academic performance. [III] Even retail spaces benefit, with customers spending more time and money in naturally-designed environments. These practical advantages explain why biophilic design is gaining momentum across various sectors. [IV]
Implementing biophilic design doesn't require elaborate renovations. Simple changes like adding houseplants, using natural materials, or rearranging furniture to maximize natural light can make significant differences. Even artificial representations of nature, such as nature photography or recordings of birdsong, provide some benefits. The key is creating spaces that stimulate our senses in ways that remind us of natural environments. This approach works in urban apartments, suburban homes, and rural settings alike. As cities grow denser, these natural connections become increasingly valuable for maintaining our psychological health.
Looking ahead, biophilic design will likely become standard practice rather than a luxury option. Climate change concerns are pushing architects to create buildings that not only connect with nature but also protect it. Living walls that purify air, rooftop gardens that reduce energy consumption, and materials that sequester carbon are becoming more common. These innovations represent a shift from merely appreciating nature to actively participating in its preservation. By designing spaces that honor our biological need for natural connection, we create environments that support both human and planetary health for generations to come.
Which of the following best summarises paragraph 3?
Cho tam giác ABC có \(BC = 5,\widehat {BAC} = {120^o}\). Bán kính ĐT ngoại tiếp \(\Delta ABC\) bằng?
Hãy nêu một số biện pháp an toàn khi sử dụng điện?
Trong các câu sau, có bao nhiêu câu là mệnh đề?
(1): Số 3 là một số chẵn.
(2): 2x+1=3.
(3): Các em hãy cố gắng làm bài thi cho tốt.
(4): 1<3⇒4<2.
Trong nguyên tử một nguyên tố M có tổng số các loại hạt là 58. Biết trong ion M+ thì số hạt mang điện tích dương ít hơn số hạt không mang điện là 1 hạt. Kí hiệu của M là
Read the following passage 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 33 to 40.
Air pollution is a significant environmental issue that affects millions of people worldwide. It results from various sources, including industrial emissions, vehicle exhaust, and the burning of fossil fuels. [I] Among the most harmful pollutants are fine particulate matter (PM2.5), carbon monoxide, sulfur dioxide, and nitrogen oxides. These pollutants not only degrade air quality but also have serious health consequences, such as respiratory diseases, cardiovascular problems, and even premature death. [II]
In major cities, traffic congestion plays a critical role in worsening air pollution. The high concentration of vehicles, particularly those running on diesel fuel, releases large amounts of pollutants into the atmosphere. [III] Additionally, industrial activities in urban areas contribute to the problem by emitting harmful gases and chemicals. [IV]
Governments and environmental organizations have been implementing various measures to combat air pollution. These include promoting the use of renewable energy, encouraging public transportation, and imposing stricter emission regulations on industries. Moreover, advancements in technology have led to the development of electric vehicles and air purification systems, which help reduce pollution levels. However, despite these efforts, achieving clean air remains a global challenge that requires cooperation from all sectors of society.
Which of the following best summarizes paragraph 3?
Phương án nào là SAI?
Cho đồ thị dịch chuyển – thời gian của một vật như hình vẽ. Trong những khoảng thời gian nào, vật chuyển động thẳng đều?
Protein không thực hiện các chức năng nào trong các chức năng dưới đây?
Mark the letter A, B, C, or D on your answer sheet to indicate the best arrangement of utterances or sentences to make a meaningful exchange or text in each of the following questions from 13 to 17
a. Another challenge is limited access to learning resources, but this can be overcome by using online platforms and seeking mentors for support.
b. Additionally, adapting to new technologies can be difficult, especially for older learners, but they can improve their digital skills and use user-friendly platforms.
c. One challenge is balancing learning with work, family, and other commitments, which can be managed by prioritizing tasks, creating schedules, and using technology for on-the-go learning.
d. In today’s rapidly changing world, lifelong learning is crucial for personal and professional growth, but it comes with challenges.
e. Overall, by staying adaptable and proactive, lifelong learners can overcome obstacles and continue to grow.