Sau khi phát hiện một bệnh dịch, các chuyên gia y tế ước tính số người nhiễm bệnh kể từ ngày xuất hiện bệnh nhân đầu tiên đến ngày thứ \(t\) là \(f\left( t \right) = 45{t^2} - {t^3}\) với \(t \ge 0\). Nếu coi \(y = f\left( t \right)\) là hàm số xác định trên \(\left[ {0;\, + \infty } \right)\) thì \(f'\left( t \right)\) được xem là tốc độ truyền bệnh (người/ ngày) tại thời điểm \(t\).

a) Tốc độ truyền bệnh tại thời điểm \(t\) là \(f'\left( t \right) = 90t - 3{t^2}\).

b) Số người bị nhiễm bệnh từ ngày xuất hiện bệnh nhân đầu tiên đến ngày thứ 13 là 4 752.

c) Đến ngày thứ 45 thì không còn người nhiễm bệnh.

d) Trong 35 ngày đầu tiên thì số người nhiễm bệnh luôn tăng.

Read the following passage about opera 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 18 to 22.

Góp phần điều tiết quy mô sản xuất, cân đối cung - cầu là nội dung chức năng gì của giá cả thị trường?

Một con lắc lò xo gồm một vật nhỏ và lò xo có độ cứng 20 N/m dao động điều hòa với chu kì 2 s. Khi pha dao động là 0,5π thì vận tốc của vật là $-20\sqrt{3}$ cm/s. Lấy π² = 10. Khi vật qua vị trí có li độ $x$ = 3π cm thì động năng của con lắc là

Read the following passage about How Failures Led to Breakthroughs 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.

Many important discoveries happened because of mistakes and unexpected accidents. Alexander Fleming found penicillin when he left his laboratory messy before going on holiday. After vacation, he saw mold growing on his experiment plate. Fleming noticed this mold killed bacteria around it very effectively. This fortunate accident later saved millions of lives around the world. Scientists call finding valuable things by chance "serendipity," which happens often in research.

The Post-it Note began as a mistake that seemed useless at first. In 1968, Spencer Silver tried making a strong glue for 3M company but created a weak one instead that didn't stick permanently. Nobody knew what to do with this disappointing result for several years. Then his colleague Arthur Fry realized this "failure" could make perfect bookmarks that wouldn't damage pages when removed. This weak adhesive eventually became one of the most popular office products worldwide, changing how people work.

In cooking, many favorite foods came from kitchen errors and quick substitutions. Ruth Wakefield invented chocolate chip cookies when she ran out of baker's chocolate and used broken pieces of semi-sweet chocolate instead. She thought they would melt completely in the dough, but they kept their shape during baking. Potato chips were created when chef George Crum made extremely thin potatoes to annoy a customer who repeatedly complained about thick fries. Surprisingly, the customer loved them and ordered more!

These fascinating stories teach us that mistakes can lead to new opportunities and unexpected innovations. Thomas Edison said about his many failed light bulb attempts, "I haven't failed. I've just found 10,000 ways that don't work." This positive attitude shows we should see errors as valuable learning chances. Smart people don't fear making mistakes in their work; they fear missing opportunities to learn from them and discover something amazing.

Which of the following inventions is NOT mentioned as resulting from a mistake?

Read the following passage about fitness trends 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.

FITNESS TRENDS

[I] Reformer Pilates is an advanced and more intense variation of traditional Pilates. [II] Since this type of equipment isn’t something you would typically have at home, you’ll need to visit a specialized Pilates center to try it. [III] While it might look easy at first, don’t be fooled - by the end of the session, your thighs will be burning, and you might struggle to walk up or down stairs for a few days afterward. [IV] This workout pushes your body to its limits, providing a more challenging experience than standard Pilates, and many find it an effective way to build both strength and flexibility.

Trampolining is another popular fitness trend, and although it may seem like child's play, it’s actually a highly effective workout. Jumping up and down on a trampoline can leave you feeling exhausted after just a few minutes. Surprisingly, it’s even better for heart health than running, while also improving coordination and helping to reduce stress levels. Trampolining is gaining widespread popularity, with new centers popping up that feature as many as 150 trampolines. These facilities offer options for everyone: you can enjoy 'freejumping,   where you bounce without an instructor, or pay for professional lessons to learn the best techniques and get the most out of your workout. Many people are discovering that trampolining combines fun and fitness in a way that makes staying active much more enjoyable.

If you're someone who is typically active but feeling down or emotionally drained, Dynamic Running Therapy might be just what the doctor ordered. This trend involves running with a therapist, combining the benefits of physical exercise with talk therapy. Though these sessions are often more expensive than typical therapy sessions because of the professional fees, they offer significant advantages. Running while talking helps distract you from any discomfort, allowing you to cover longer distances, and creates a relaxed, open environment that can make it easier to talk compared to the usual therapist’s office setting.

According to paragraph 2, which of the following is NOT a benefit of Trampolining?

Để làm đường điện dây cao thế ở Hà Giang từ vị trí bản A đến bản B, người ta phải tránh một ngọn núi nên người ta phải nối thẳng đường dây từ bản A đến bản C dài 12 km rồi nối từ bản C đến bản B dài 8 km. Qua đo đạc người ta xác định được $\widehat{ABC}={65}^0$. Hỏi so với việc nối thẳng từ bản A đến bản B, người ta tốn thêm bao nhiêu tiền, biết mỗi km dây có giá 150 000 đồng?

Công khai mã nguồn là quan trọng đối với phần mềm mã nguồn mở vì điều nào sau đây?

Choose A, B, C or D that has the OPPOSITE meaning to the underlined word/phrase in each question.

AI systems assist doctors in detecting dangerous drug interactions that could put patients in jeopardy.

Choose A, B, C or D that has the CLOSEST meaning to the given sentence in the question.

As soon as the clock struck noon, the employees quickly gathered their belongings to head to lunch.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined bold word(s) in each of the following questions.

Private sponsors have experts in different areas of technology ranging from nutrition to the treatment of injuries.

Hai vật được thả rơi tự do đồng thời từ hai độ cao khác nhau h₁ và h₂. Khoảng thời gian rơi của vật thứ nhất bằng một nửa khoảng thời gian rơi của vật thứ hai. Bỏ qua lực cản của không khí. Tỉ số các độ cao $\dfrac{h_1}{h_2}$ bằng

Những người sản xuất, cung cấp hàng hoá, dịch vụ ra thị trường, đáp ứng nhu cầu tiêu dùng của xã hội được gọi là