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Dados sen x = 4/5 (0<x<pi/2) e cos y =5/13 (0<y<pi/2), calcule. a)sen (x+y)b)cos (x+y)c)sen

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- Matemática

Dados sen x = 4/5 (0
b)cos (x+y)

c)sen (x-y)

d)cos (x-y)​

1 Resposta

marinatagomori

displaystyle y=frac{pi}{4}-x  sin y=sinleft(frac{pi}{4}-xight)  sin y=sinleft(frac{pi}{4}ight)cos x-cosleft(frac{pi}{4}ight)sin x  sin y=frac{sqrt{2}}{2}cos x-frac{sqrt{2}}{2}sin x  sin y=frac{sqrt{2}}{2}left(cos x-sin xight)  sin y=frac{sqrt{2}}{2}left(frac{12}{13}-frac{5}{13}ight)  oxed{sin y=frac{7sqrt{2}}{26}}

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