1) sin2B-sin2Bcos2B=?

2) cos4B+cos2Bsin2B=?

3) tg2B*ctg2B-cos2B=?

Question

Математика

Юраня

17 ноября, 06:10

1) sin2B-sin2Bcos2B=?

2) cos4B+cos2Bsin2B=?

3) tg2B*ctg2B-cos2B=?

+5

Ответы (1)

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Мариетта · Answer 1

Sin2B - sin2B*cos2B = sin2B (1 - cos2B) = sin2B (1 - (cos^2 B-Sin^2 B) = sin2B ((1-cos^2 B) + sin^2 B) = sin2B (sin^2 B + sin^2 B) = 2sinB*cosB*2sin^ B = 4sin^3 B*cosB

tg2B*ctg2B-cos2B = 1-cos^2 B + sin^2 B = sin^2 B + sin2 B = 2sin^2 B

1) sin2B-sin2B*cos2B=?2) cos4B+cos2B*sin2B=?3) tg2B*ctg2B-cos2B=?

1) sin2B-sin2Bcos2B=?

2) cos4B+cos2Bsin2B=?

3) tg2B*ctg2B-cos2B=?