[Fact #1 maybe] everyone’s posting knowledge so here comes wisdom: (TL;DR: alarmingly terrible please wear a mask.) Long answer: You might be aware that Hanoi has repeatedly topped the world’s leaderboard of the most polluted city lately. Not only do the widespread usage of petrol and diesel-powered vehicles emit carbon dioxide, the combustion of the fuels at such high temperatures is also apparently enough to, in a sense, “burn” the air! The overwhelming abundance of nitrogen and oxygen in our atmosphere means when these molecules split… N≡N + O=O → N=O + N=O … they path the way for a cascade of reactions: O=O + N=O → O + O=N=O O + O=O → O-O=O (ozone but bad) O=N + O=O + N=O → O=N=O + O=N=O NO2 + CH3C(O)OO → CH3C(O)OONO2 (or “PAN”) These gases cast the familiar brown haze seen throughout the day, and some of them in particular, are classified a 4 on the “fire diamond,” which means “Very short exposure could cause death or major residual injury.” … which is extremely concerning government you gotta do somethingggg stay safe ppl!!! (Ms. Louise did not make me post this btw)

Rui has: 2 machines, 1 robot, and a star. Is this sentence grammatically correct? I mean yeah??? It looks ok, no major mistakes or anything… WRONG👿❌❌❌🙅 An ENGLISH colon (not bio😒) has to appear behind a FULL sentence, so technically the example up there is wrong. SAT’s usually tricks you by using these questions so be careful everyone Stay safe and sane o(｀ω´ )o

Some shopping malls use high-frequency “mosquito sounds” to stop teenagers from gathering in certain areas. It may sound strange, but the reason behind it is mostly economic. Malls want their space to be occupied by people who will likely spend money. When large groups of teenagers hang around without buying anything, they take up space, create noise, and make the area feel more crowded. This can discourage adult consumers, who usually spend more, from staying longer in the stores. In economics, every part of a mall is considered valuable. The goal is to increase revenue from each square metre. If a space is filled with people who are not contributing to sales, the mall sees that as an inefficient use of resources. Instead of hiring more staff or redesigning the whole area, playing mosquito-frequency sounds is a low-cost method to change customer behaviour. While this method may feel controversial, it shows how businesses use simple tools to manage customer flow and maximise economic efficiency.

Differentiation is the process of measuring how fast a function changes. Some of the readers may have learned it in IGCSE Year 2 Maths. This paragraph will explain deeper about how mathematicians developed the idea behind this concept. On the curve above, point A represents the value of f(x) at x, and point B represents the value of f(x+h) at point (x+h). The straight line (the yellow line) connecting two points A and B is called a secant line. The slope of this line can be calculated by the formula: Gradient = rise/run: ⇒ f(x+h) - f(x)/(x+h)-x ⇒ f(x+h) - f(x)/h This secant line represents the average rate of change between the two points A and B. As h becomes smaller (approaches zero), it means that point B gets closer to point A, and the secant line becomes a tangent line. This process gives the exact slope of a curve at a point, which is called the derivative.

Have you ever heard this term before and wonder what exactly is behavioural economics? Classical economics assumes that humans are rational thinkers. They have full access to perfect information, have sufficient time for making the best decision. However, this is not always the case in reality. Humans in real life are considered irrational and act on their self interest. Why? Because, us, a normal human, have different preferences for goods and services. Some people will highly likely to purchase an idol’s album even though this is not the best option for their sake simply because we are really into it. This makes the economic models cannot be applied straightforwardly to real-life settings. In that case, behavioural economics will take place for the explanation. Behavioral economics is defined as a field that integrates psychological principles with economic theory to challenge traditional assumptions of rationality and selfish preferences, emphasizing the role of emotions, decision-making under risk, and the impact of framing on outcomes. In simpler words, it investigates people’s behaviour in the economy, examining thoughts, preferences and irrationality. This plays a pivotal role in how economic agents make their decisions, such as businesses and policy makers. For example, by acknowledging how consumers perceive the value of products, firms might design the best-fit message delivering to their customers. Also, acknowledging human behaviours might aid companies and governments to account for potential risks and suitable modifications. -By Vu Thanh Hao Ngoc 12AL1-