Х + ( 5/6 )Х > 65
11/6 Х > 65
Х > 65 : 11/6
Х > 390/11
Х > 35 5/11
Ответ 36
Sinx/3=-1/2
x/3=-π/6+2πn⇒x=-π/2+6πn,n∈z
0≤-π/2+6πn≤3π
0≤-1+12n≤6
1≤12n≤5
1/12≤n≤5/12
нет решения на [0;3π]
x/3=7π/6+2πk⇒x=7π/2+6πk
0≤7π/2+6πk≤3π
0≤7+12k≤6
-7≤12k≤-1
-7/12≤k≤-1/12
нет решения на [0;3π]
4sinx+5cosx=4
8sinx/28cosx/2+5cos²x/2-5sin²x/2-4sin²x/2-4cos²x/2=0/cos²x/2
9tg²x/2-8tgx/2-1=0
tgx/2=a
9a²-8a-1=0
D=64+36=100
a1=(8-10)/18=-1/9⇒tgx/2=-1/9⇒x/2=-arctg1/9+πn⇒x=-2arctg1/9+πn,n∈z
a2=(8+10)/18=1⇒tgx/2=1⇒x/2=π/4+πk⇒x=π/2+2πk,k∈z
Решение
<span>(a</span>⁵<span>)</span>²<span>:(a</span>³<span>)</span>² = a¹⁰ : a⁶ = a¹⁰⁻⁶ = a⁴
1) a(b-c)+2(b-c)=(b-c)(a+2)
2) 2x^2+2xy-xy-y^2 = 2x(x+y) -y(x+y)=(x+y)(2x-y)