cos (α + π) + sin (α - 3π/2) - ctg (π/2 + α) * tg (3π/2 + α) = ?

sin 420 + cos (-390) + tg (-1230) - ctg420=?

sin 5π / 18cos π / 9 - sin π/9 cos 5 π / 18 = ?

tg² α + sin²α - 1 / cos²α=?

Question

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28 марта, 09:43

cos (α + π) + sin (α - 3π/2) - ctg (π/2 + α) * tg (3π/2 + α) = ?

sin 420 + cos (-390) + tg (-1230) - ctg420=?

sin 5π / 18cos π / 9 - sin π/9 cos 5 π / 18 = ?

tg² α + sin²α - 1 / cos²α=?

+1

Ответы (2)

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Лавря · Answer 1

= - cos a + cos a + tg a * (-ctg a) = - ctg a*tg a = - 1

= sin 60 - cos 30 - tg 150 - ctg 60 = sin 60 - cos 30 - tg (180 - 30) - ctg 60 = kor3/2 - kor3/2 + kor3/3 - kor3/3 = 0

Светуша · Answer 2

1) ... = - cos a + cos a + tg a * (-ctg a) = - ctg a*tg a = - 1

2) ... = sin 60 - cos 30 - tg 150 - ctg 60 = sin 60 - cos 30 - tg (180 - 30) - ctg 60 = kor3/2 - kor3/2 + kor3/3 - kor3/3 = 0

cos (α + π) + sin (α - 3π/2) - ctg (π/2 + α) * tg (3π/2 + α) = ?sin 420 + cos (-390) + tg (-1230) - ctg420=?sin 5π / 18*cos π / 9 - sin π/9 * cos 5 π / 18 = ?tg² α + sin²α - 1 / cos²α=?

cos (α + π) + sin (α - 3π/2) - ctg (π/2 + α) * tg (3π/2 + α) = ?

sin 420 + cos (-390) + tg (-1230) - ctg420=?

sin 5π / 18cos π / 9 - sin π/9 cos 5 π / 18 = ?

tg² α + sin²α - 1 / cos²α=?