Tutor profile: Arianna N.
When to Use “qué” and “cuál” in Spanish?
The word cuál is a relative pronoun that alternates in its use with "qué". However, both are not interchangeable. The word "cuál" has more restricted usage contexts compared to "qué". Here I will refer to the pronoun in question as "cuál" for short, but in reality the forms it can take are five: el cuál, la cuál, lo cuál, los cuales y las cuales. This pronoun always appears at the top of a relative relative sentence. Its possibilities of use vary depending on the nature of that sentence. As we know, there are two types of relative sentences: However, we can only use "cuál" in relative explanatory sentences. With the former, we can only use "cuál" if it has a preposition before it. Example: "Este es el libro sobre el cuál hemos hablado en clase." The pronoun "cuál" can be substituted here perfectly by "que". Example: "Este es el libro sobre el que hemos hablado en clase." Instead, this other sentence is incorrect because there is no preposition: "JK Rowling es una escritora la cual se caracteriza por su prosa rica y refinada" The only possibility is to use "que": "JK Rowling es una escritora que se caracteriza por su prosa rica y refinada" The second possibility is that of its use in relative explanatory sentences. There are no restrictions here. We can use which quietly. The following two examples are correct: -"Me estuvo explicando todas sus aventuras, las cuales me eran perfectamente indiferentes." -"Tus gustos, sobre los cuales prefiero no discutir, resultan bastante sorprendentes."
Subject: Environmental Science
78% of the atmosphere is made up of nitrogen. How does the nitrogen cycle work in our atmosphere?
Nitrogen is an extremely variable element and is found on the planet, in different characteristics, that is why it is found in an organic and inorganic way and in different degrees of oxidation. This cycle refers to the natural pattern, which meets nitrogen when incorporated into different elements, starting with the soil, then moving on to the plants, then entering living organisms through food and then returning to the atmosphere. The nitrogen cycle is divided into six phases, which are: fixation, nitrification, assimilation, ammonification, immobilization, denitrification. Fixation. At this stage, the nitrogen contained in the earth's atmosphere is absorbed by the plants, once the nitrogen that is in the form of gas is transformed into ammonia, due to the action of certain microorganisms that make life in the soil and water, who are responsible for breaking it down, so that plants use nutrients to stay alive. Nitrification. In this way, the process is called by which some bacteria present in the soil participate in the oxidation of ammonia, from which ammonia is obtained, which is in turn oxidized by other bacteria, transforming it into nitrate. For this phase to succeed, there are external factors, such as soil composition, temperature, humidity, pH, nutrients and the amount of oxygen. Simply put, once the nitrogen is transformed into nitrate or ammonium, plants take it from the soil. Assimilation Precisely during this phase of the nitrogen cycle, the plants are impregnated with nitrate or ammonia, taking advantage of the absorption capacity of their roots and there begins the process of assimilation and transformation of the element into nutrients, easily usable by living beings that consume. Ammonification The decomposition of organic matter is of vital importance at this point in the nitrogen cycle, with the understanding that decomposed wastes, microorganisms, which degrade them to simple compounds and metabolize them, release the excess nitrogen in form of ammonia or ammonium ion. In this sense, organic waste forms a foothold to indirectly absorb nitrogen in the form of processed ammonia. Immobilization This phase is a response to the intervention of the metabolic processes of microorganisms in the use of nitrogen, forming organic nitrogen, that is, a phase contrary to nitrification. For this reason, the vegetation does not absorb it, nor assimilate it to previous decomposition, then it is immobilized. Denitrification The intervention of microorganisms that are responsible for deoxidizing nitrates and ammonia, returning it to the atmosphere in the form of gas, is known as the "denitrification process" or "participation of denitrifying bacteria." During this process, metabolic, which is carried out mainly under anaerobic conditions, reduces nitrate to nitrogen gas and is a phenomenon that is observed in a linear fashion, until the gas is incorporated back into the atmosphere.
How would you solve to find the relative extrema? in the equation: f(x)= -(x^2)-x+3
First, find the derivative of your equation. If you don't know how to find the derivative then, we should start with a problem focused on derivatives. After you find the derivative (f'(x)), then differentiate to find the value of x by making the derivative equal to zero. [ f'(x)= -2x-1 =0] After you find the value of x (x= -1/2) then you know that the equation is undefined at -1/2 meaning that the intervals for this equation are (-infinity, -1/2) (-1/2, infinity). Now that you have the interval values, test using the derivative to see if the interval is positive or negative. For example, if we want to test interval (-infinity, -1/2) then we have to choose a number within that interval. Let's say we choose x= -4, then we substitute the value of x by -4 in the derivative equation [ f'(x)= -2x-1] this is expressed as f'(-4)=7. So we know that the interval (-infinity, -1/2) is positive. We do the same with the remaining intervals. Now, let's say that a=-infinity, b=infinity, and c=-1/2 (c is always the critical point of your equation). If the interval at (a,c) is positive and negative at (c,b) then c is the relative maximum. However, if interval at (a,c) is negative and positive at (c,b) then c is the relative minimum. From your last step you can then calculate the relative maxima by using your main function [f(x)= -(x^2)-x+3] and plugging in the result of your critical point as x (x=-1/2) (the relative maxima should be 13/4. And there is no relative minima.
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