Question

СРОЧНО! Помогите (1,3 и 5)

Answer 1

1.
a) sin(α + β) - 2sinβcosα = sinαcosβ + sinβcosα - 2sinβcosα = - sinβcosα + sinαcosβ = sin(α - β) = sin(π/2) = 1

б) sin²α - (-sinα)sinα/(-tgα*(-tgα)) = sin²α + sin²α*cos²α/sin²α = sin²α + cos²α = 1

3.

a) cosα = √(1 - 144/169) = √25/169 = 5/13

б) sin2α = 2sinαcosα = 2*12/13 * 5/13 = 120/169

в) cos2a = 2cos²α - 1 = 2 * 25/169 - 1 = 50/169 - 1 = -119/169

5.
2sin34°sin26° - sin82° = cos(34° - 26°) - cos(34° + 26°) - sin82° = 

cos8° - cos60° - sin(90° - 8°) = cos8° - 0,5 - cos8° = -0,5