Предмет: Математика, автор: Аноним

Пожалуйста решите!!!
1.sin3x+sin x=0
2.6sin^2x-5sinx+1=0
3.sin^2x+sinx•cosx=0
4.2sinx•sin(π /2-х)=1
5.sinx=1/2

Ответы

Автор ответа: оллдд

0

sin^2x-5 cosx=sinx*cosx-5sinxsin^2x - 5cosx - sinxcosx + 5sinx = 0sin^2x + 5sinx - 5cosx - sinxcosx = 0sinx(sinx + 5) - cosx(5 + sinx) = 0(sinx - cosx)(sinx + 5) = 0sinx - cosx = 0 | : cosxtgx - 1 = 0tgx = 1x = arctg1 + pinx = pi/4 + pin, n = Zsinx + 5 = 0sinx = -5x = (-1)^n * -arcsin5 + pin, n=Z

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Exercise 1. Подберите правильный ответ.
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a) small children.
b) older children.
c) small and older children.
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a) they live far from the school.
b) they don’t like to walk.
c) it’s dangerous for them.
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a) at the door of the school.
b) near the toilet.
c) outside the washroom.
The white teachers work there because
a) they can’t find a better job.
b) they love their job.
c) they get a lot of money there.
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a) more money
b) more teachers.
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