Assinale a alternativa cujo vocábulo só pode ser empregado com acento gráfico.

Considere o sistema linear homogêneo

!$ \begin{cases} x - 3y + kz= 0 \\ 3x + ky + z= 0 \\ kx + y= 0 \end{cases} !$ ,

onde k é um número real. O único valor que torna o sistema, acima, possível e indeterminado, pertence ao intervalo

Sejam z e v números complexos onde |z|=1 e v tem coordenadas no plano de Argand-Gauss !$ \left ( \dfrac{\sqrt{2}}{2},\dfrac{\sqrt{2}}{2} \right) !$. Sobre o número complexo !$ z\cdot v !$ (resultante da multiplicação dos complexos z e v), podemos afirmar que

Would it be wrong to eradicate mosquitoes?

The mosquito is the most dangerous animal in the world, carrying diseases that kill one million people a year. Now the Zika virus, which is carried by mosquitoes, has been linked with thousands of babies born with brain defects in South America. There are 3,500 known species of mosquitoes, but only the females from just 6% of species draw blood from humans - to help them develop their eggs. Of these, just half carry parasites that cause human diseases.
More than a million people, mostly from poorer nations, die each year from mosquito-borne diseases, including Malaria, Dengue Fever and Yellow Fever. Some mosquitoes also carry the Zika virus, which was first thought to cause only mild fever and rashes. However, scientists are now worried that it can damage babies in the womb. There’s a constant effort to educate people to use nets and other tactics to avoid being bitten. But would it just be simpler to make an entire species of disease-carrying mosquito extinct?
In Britain, scientists at Oxford University and the biotech firm Oxitec have genetically modified (GM) the males of Aedes aegypti - a mosquito species that carries both the Zika and Dengue viruses. These GM males carry a gene that stops their offspring from developing properly. This second generation of mosquitoes then die before they can reproduce and become carriers of disease themselves.
So are there any downsides to removing mosquitoes? Mosquitoes, which mostly feed on plant nectar, are important pollinators. They are also a food source for birds and bats while their young - as larvae - are consumed by fish and frogs. This could have an effect further ahead in the food chain. Mosquitoes also have limited the destructive impact of humanity on nature. Mosquitoes make tropical rainforests, for humans, virtually uninhabitable. Rainforests are home to a large share of our total plant and animal species, and nothing has done more to delay man-made destruction over the past 10,000 years than the mosquito.

Adapted from http://www.bbc.com/news/magazine-35408835

In the sentence “This could have an effect further ahead in the food chain.” (paragraph 4), the word further expresses

This migrant crisis is different from all others

2015 was unquestionably the year of the migrant. The news was dominated for months by pictures of vast crowds shuffling through the borders of yet another European country, being treated with brutality in some places and given a reluctant welcome in others.
When researching a report for radio and television about the migrant phenomenon, it is possible to realize that there was nothing new about it. For many years, waves of displaced and frightened people have broken over Europe again and again and the images have been strikingly similar each time.
In 1945, (1) the ethnic Germans, forced out of their homes in Poland, Czechoslovakia and Russia and obliged to seek shelter in a shattered and divided Germany. More recently, we can see floods of Albanian refugees escaping from the ethnic cleansing of the Serbian forces in Kosovo in 1998 and 1999.
Yet there is one major difference between these waves of migrants in the past and the one we saw in 2015. Professor Alex Betts, director of the Refugee Studies Centre at Oxford University says that it was the first time Europe faced people coming in from the outside in large numbers as refugees. He explains: “The fact that many are Muslims is perceived as challenging Europe’s identity.” European societies are changing very fast, indeed, as a result of immigration. In London, for instance, more than 300 languages are now spoken, according to a recent academic study. The influx of migrants reinforces people’s sense that their identity is under threat.
But how can the world deal conclusively with the problem? The former UN under-secretary-general for humanitarian affairs, Sir John Holmes, blames global governance. “Other powers are rising,” he says - Syria is an example of this. “And the United States doesn’t have the influence it once did, so the problem’s not being fixed, no-one’s waving the big stick and we’re having to pick up the pieces.” We have endured an entire century of exile and homelessness and the cause is always the same - conflict and bad government. Unless these are dealt with, the flow of migrants will never be stopped.

Adapted from http://www.bbc.com/news/world-35091772

According to the text, read the statements and choose the correct alternative.

I – There isn’t anything new about the current migrant crisis.

II – The former migrant phenomena happened in London.

III – This migrant phenomenon is interfering in Europe’s society.

IV – Europeans are concerned about learning new languages.

V – Syria is becoming powerful and apparently there is no control over it.

VI – Conflicts and poor governance are the reasons for the migration.

A soma das soluções da equação cos(2x) - cos(x)=0, com x !$ \in !$ [0, 2 !$ \pi !$), é igual a

Na figura, o raio da circunferência de centro O é !$ \dfrac{25}{2} !$ cm e a corda MP mede 10 cm. A medida, em centímetros, do segmento PQ é

Munições traçantes são aquelas que possuem um projétil especial, contendo uma carga pirotécnica em sua retaguarda. Essa carga pirotécnica, após o tiro, é ignificada, gerando um traço de luz colorido, permitindo a visualização de tiros noturnos a olho nu. Essa carga pirotécnica é uma mistura química que pode possuir, dentre vários ingredientes, sais cujos íons emitem radiação de cor característica associada ao traço luminoso.

Um tipo de munição traçante usada por um exército possui na sua composição química uma determinada substância, cuja espécie química ocasiona um traço de cor correspondente bastante característico.
Com relação à espécie química componente da munição desse exército sabe-se:
I) A representação do elemento químico do átomo da espécie responsável pela coloração pertence à família dos metais alcalinos-terrosos da tabela periódica.
II) O átomo da espécie responsável pela coloração do traço possui massa de 137 u e número de nêutrons 81.
Sabe-se também que uma das espécies apresentadas na tabela do item III (que mostra a relação de cor emitida característica conforme a espécie química e sua distribuição eletrônica) é a responsável pela cor do traço da munição desse exército.
III) Tabela com espécies químicas, suas distribuições eletrônicas e colorações características:

Considerando os dados contidos, nos itens I e II, atrelados às informações da tabela do item III, a munição traçante, descrita acima, empregada por esse exército possui traço de coloração

A crise do sistema feudal motivou uma série de mudanças sociais e culturais com o revigoramento do comércio e das cidades, entre os séculos XI e XIII, na Europa. Nas alternativas abaixo, assinale aquela que se relaciona com o surgimento da burguesia.

Marque a única alternativa correta quanto ao emprego do verbo.