anna2501v

Verified answer

Ответы:
23. 2
24. 1
25. -0,6

oganesbagoyan

Verified answer

Task/26548452
-------------------
23.
( 3cos(π -β) +sin(π/2 +β) ) / cos(β+3π) =( -3cosβ +cosβ) /cos(2π +π+β ) =
 -2cosβ cos(π+β)= -2cosβ /( -cosβ) =2.
------------
24.
(2sin(α -7π) +cos(3π/2 +α) ) / sin(α+π) =(2sin( -(6π +π-α)) +sinα) / sin(π+α) = (- 2sin(6π +π-α)+sinα) / (-sinα) =( - 2sin(π-α) +sinα) / (-sinα) =
( - 2sinα +sinα) / (-sinα) = (-sinα)/(-sinα) = 1.
------------
25.
cosα = - √(1 - sin²α) = -√(1- 0,8²) = -√(1-0,64) = --√(0,36 = - 0,6.