Question

Por favor alguém me ajuda

Answer 1

Resposta:

1º quadrante :

$\dfrac{5\pi }{4}-\pi =\dfrac{5\pi -4\pi }{4}=\boxed{\dfrac{\pi }{4}}$

$Valor~~ do ~~seno\to\dfrac{\sqrt{2} }{2}$

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2º quadrante

$\pi -\dfrac{\pi }{4}=\dfrac{4\pi -\pi }{4}=\boxed{\dfrac{3\pi }{4}}$

$Valor~~do~~seno~\to~\dfrac{\sqrt{2} }{2}$

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3º quadrante

$\pi +\dfrac{\pi }{4}=\dfrac{4\pi +\pi }{4}=\dfrac{5\pi }{4}$

$Valor~~do~~seno~\to~-\dfrac{\sqrt{2} }{2}$

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4º quadrante

$2\pi -\dfrac{\pi }{4}=\dfrac{8\pi -\pi }{4}=\boxed{\dfrac{7\pi }{4}}\\ \\ \\ Valor~~do~~seno~\to~-\dfrac{\sqrt{2} }{2}$