Cos²x+2sinx+2=0
1-sin²x+2sinx+2=0
sinx=a
a²-2a-3=0
a1+a2=2 U a1*a2=-3
a1=-1⇒sinx=-1⇒x=-π/2+2πn
-4π≤-π/2+2πn≤2π
-8≤-1+4n≤4
-7≤4n≤5
-7/4≤n≤5/4
n=-1⇒x=-π/2-2π=-5π/2
n=0πx=-π/2
n=1πx=-π/2+2π=3π/2
a2=3⇒sinx=3>1 нет решения
(5x-x²)/(x+8)>0
x(5-x)/(x+8)>0
x=0 x=5 x=-8
+ _ + _
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-8 0 5
x∈(-∞;-8) U (0;5)
1) log₅0,04∨-2
log₅1/25∨-2
log₅5⁻²≡-2
2) lg0,01∨-2
lg10⁻²≡-2
2(а+б)+х(а+б)= (2+х)(а+б)