Все подставляешь
21*4/9*3-4*3-12*(-2/3)+7*(-2/3)*9=58,5
<h3>8cos²x + 14sinx + 1 = 0</h3>
sin²x + cos²x = 1 ⇒ cos²x = 1 - sin²x
<h3>8( 1 - sin²x ) + 14sinx + 1 = 0</h3><h3>8 - 8sin²x + 14sinx + 1 = 0</h3><h3>- 8sin²x + 14sinx + 9 = 0</h3><h3>8sin²x - 14sinx - 9 = 0</h3><h3>Пусть sinx = a , a ∈ [ - 1 ; 1 ] , тогда</h3><h3>8a² - 14a - 9 = 0</h3><h3>D = (-14)² - 4•8•(-9) = 196 + 288 = 484 = 22²</h3><h3>a₁ = (14 - 22)/16 = - 8/16 = - 1/2 ⇔ sinx = - 1/2 </h3><h3>[ x = (-π/6) + 2πn</h3><h3>[ x = (-5π/6) + 2πn , n ∈ Z</h3><h3>a₂ = (14 + 22)/16 = 36/16 = 9/4 = 2,25 ∉ [ - 1 ; 1 ]</h3><h3><u><em>ОТВЕТ: (-π/6) + 2πn ; (-5π/6) + 2πn , n ∈ Z</em></u></h3><h3><u><em /></u></h3>
ОДЗ
x+3≥0⇒x≥-3
x-1≥0⇒x≥1
x-2≥0⇒x≥2
x∈[2;∞)
x+3<x-1+2√(x²-3x+2)+x-2
x+3-2x+3<2√(x²-3x+2)
6-x<2√(x²-3x+2)
36-12x+x²<4x²-12x+8
4x²-12x+8-36+12x-x²>0
3x²-28>0
(x-2√21/3)(x+2√21/3)>0
x<-2√21/3 U x>2√21/3
x∈(2√21/3;∞)
...
D=4+12=16
x1=-2+4/6=1/3
x2=-2-4/6=-1
ответ x1=1/3 x2=-1