Considere a matriz quadrada de ordem 3,
, onde x é um número real.
Podemos afirmar que
Seja (a,b,c) uma progressão geométrica de números
reais com a ≠ 0 . Definindo s = a + b + c , o menor valor
possível para s/ a é igual a
Considere o gráfico da função y = f(x ) exibido na figura a seguir.
O gráfico da função inversa y = f-1(x)é dado por
O gráfico abaixo exibe o lucro líquido (em milhares de reais) de três pequenas empresas A, B e C, nos anos de 2013 e 2014.
Com relação ao lucro líquido, podemos afirmar que
We’ve modified our behavior so we can text and walk
Texting – or checking social media or reading/responding to mail or reading the news or checking the weather or watching a video – while walking is a pretty common phenomenon. It’s so common that most people who own a mobile device have become texting walkers.
Research suggests that these texters adopt protective measures to minimize the risk of accidents when walking. They’re less likely to trip because they shorten their step length, reduce step frequency, lengthen the time during which both feet are in contact with the ground, and increase obstacle clearance height. Taken together this creates an exaggerated image of walking, but it apparently slows the walker enough so that he registers some of what is happening around him and can compensate for it.
(Adaptado de http://blogs.scientificamerican.com/anthropology-in-practice/we-ve-modified-our-behavior-so-we-can-text-and-walk/.)
If apes go extinct, so could entire forests
Bonobos eat a lot of fruit, and fruit contains seeds. Those seeds travel through a bonobo’s digestive system while bonobo itself travels around the forest. A few hours later, the seeds end up being deposited far from where the fruits were plucked. And that is where the new trees come from.
According to a paper recently published, if the bonobos disappeared, the plants would also likely go extinct, for many trees and plants species in Congo rely almost exclusively on bonobos for seed dispersal.
The bonobo has two major functions here. First of all, many seeds will not germinate well unless they have been “handled” by another species. Stomach acids and intestinal processes make the seed more able to absorb water and later sprout.
Secondly, many seeds will not succeed if they remain too close to their parental trees. The seeds that fell to the ground near their parents did not survive because they were choked off by the nearby plants. The bonobos eat about 3,5 hours every day and travel a mean of 1.2 kilometers from meal sites before defecating.
(Adaptado de http://blogs.scientificamerican.com/extinction-countdown /if-apes-go-extinct-so-could-entire-forests/.)
Qual é a explicação para o título?
We’ve modified our behavior so we can text and walk
Texting – or checking social media or reading/responding to mail or reading the news or checking the weather or watching a video – while walking is a pretty common phenomenon. It’s so common that most people who own a mobile device have become texting walkers.
Research suggests that these texters adopt protective measures to minimize the risk of accidents when walking. They’re less likely to trip because they shorten their step length, reduce step frequency, lengthen the time during which both feet are in contact with the ground, and increase obstacle clearance height. Taken together this creates an exaggerated image of walking, but it apparently slows the walker enough so that he registers some of what is happening around him and can compensate for it.
(Adaptado de http://blogs.scientificamerican.com/anthropology-in-practice/we-ve-modified-our-behavior-so-we-can-text-and-walk/.)
Advice for new students from those who know (old students)
The first day of college I was a ball of nerves. I remember walking into my first class and running to the first seat I found, thinking everyone would be staring at me. But nobody seemed to notice and then it hit me: The fact that nobody knew me meant nobody would judge, which, upon reflection, was what I was scared of the most. I told myself to let go. All along the year, I forced myself into situations that were uncomfortable for me – for example, auditioning for a dance piece. Believe it or not, that performance was a highlight of my freshman year. My advice: challenge yourself to try something new, something you couldn’t have done in high school. – Ria Jagasia, Vanderbilt University, ’18.
(Adaptado de http://www.nytimes.com/2015/08/02/ education/edlife/ advice-for-new-students-from-those-who-know-old-students.html?ref= edlife.)
Advice for new students from those who know (old students)
The first day of college I was a ball of nerves. I remember walking into my first class and running to the first seat I found, thinking everyone would be staring at me. But nobody seemed to notice and then it hit me: The fact that nobody knew me meant nobody would judge, which, upon reflection, was what I was scared of the most. I told myself to let go. All along the year, I forced myself into situations that were uncomfortable for me – for example, auditioning for a dance piece. Believe it or not, that performance was a highlight of my freshman year. My advice: challenge yourself to try something new, something you couldn’t have done in high school. – Ria Jagasia, Vanderbilt University, ’18.
(Adaptado de http://www.nytimes.com/2015/08/02/ education/edlife/ advice-for-new-students-from-those-who-know-old-students.html?ref= edlife.)
O texto anuncia um
Na tirinha, Calvin dá dicas sobre como
"If you believe in freedom of speech, you believe in freedom of speech for views you don’t like. Goebbels was in favor of freedom of speech for views he liked. So was Stalin. If you’re in favor of freedom of speech, that means you’re in favor of freedom of speech precisely for views you despise."
(NoamChomsky)
(Fonte: http://noam-chomsky.tumblr.com/post/7223808896/if-youbelieve-in-freedom-of-speech-you-believe.)
O autor do texto
A tira tematiza a contribuição da atividade humana para a deterioração do meio ambiente. Do diálogo apresentado, pode-se depreender que os ursos já sabiam
Os compostos (NH4)H2PO4 e NaHCO3 são usados em extintores como agentes de combate ao fogo. Quando lançados sobre uma chama, ocorrem as seguintes transformações:
(NH4)H2PO4 → NH3 + H3PO4
H3PO4 → polifosfato (viscoso)
NaHCO3 → CO2 + H2O + Na2CO3 (particulado).
No combate a todos os tipos de incêndio, a nuvem formada
de gás é importante, mas naqueles envolvendo materiais
sólidos, o depósito do material oriundo da transformação
do agente de combate sobre o combustível tem papel
decisivo. Assim, o agente (NH4)H2PO4 pode substituir o
NaHCO3 em qualquer situação, mas o contrário não é
verdade. Isso permite concluir que no combate ao incêndio
que envolve