1)cosx<0⇒x∈(π/2+2πn;3π/2+2πn,n∈z)
-cosx+√3sinx=0
2(√3/2sinx-1/2cosx)=0
2sin(x-π/6)=0
x-π/6=πn
x=π/6+πn U x∈(π/2+2πn;3π/2+2πn,n∈z)⇒x=7π/6+2πn
2π≤7π/6+2πn≤7π/2
12≤7+12n≤21
5≤12n≤14
5/12≤n≤7/6
n=1⇒x=7π/6+2π=19π/6
2)cosx≥0⇒x∈[-π/2+2πk;π/2+2πk,k∈z]
cosx+√3sinx=0
2sin(x+π/6)=0
x+π/6=πk
x=-π/6+πk U x∈[-π/2+2πk;π/2+2πk,k∈z]⇒x=π/6+2πk
2π≤π/6+2πk≤7π/2
12≤1+12k≤21
11≤12k≤20
11/12≤k≤5/3
k=1⇒x=π/6+2π=13π/6
Исходное не пишу
= <em>10m²</em>-15mn+2mn-3n²-<em>10m²</em>-20mn-10n²=-13n²-33mn=-n(13n+33m)
(X+2)^2==x^2+4x+4
(3y-X)^2=9y^2-6xy+x^2
50ⁿ⁺³ (5² *2)³ *(5² * 2)ⁿ 5⁶* 2³ * 5²ⁿ * 2ⁿ *2²
--------------- = -------------------------- = ------------------------ = 5¹ * 2³⁺²= 5* 32 =160
5²ⁿ⁺⁵ * 2ⁿ⁻² 5⁵* 5²ⁿ* 2ⁿ *2⁻² 5⁵* 5²ⁿ* 2ⁿ