(2/3)^(2-2x)≤[2/3^(3)]^(x-2)
(2/3)^(2-2x)≤(2/3)^3x-6 baza subynitara ⇒
2-2x≥3x-6
x≤8/5
ex 3, numarul de sub radical treb< Numitiorul e pozitiv pt oricare x real,Pui conditia ca si numaratorul sa fie pozitivuie sa fie pozitiv
2- lx-2l≥0 =>
l x-2 l≤2 =>
-2≤x-2≤2 =>
0≤x≤4
x∈[0 .4]
Ex2
x1=(-1-√3i)/2
x2=(-1+i√3)/2)
Pui numerele sub forma trigonometrica
l x1 l=l x2 l=1
x1=cosα+isinα α apartine cadran 3
x2=cosβ+isinβ β∈cadran2
x1=cos 4π/3+isin 4π/3
X1^2016 - aplici Moivre si obtii
x1^2016=cos 2016 *4π/3+isin 2016*4π/3=
cos20688π+isin2688π= 1
Ex 11x≥x²+28
x²-11x+28≤0
functie de grd 2 , negativa intre radacini
X1=4 x2= 7
x∈[4,7]
