√2x^2-5x+1<√x^2-2x-1

2x²-5x+1≥0
D=25-8=17
x1=(5-√17)/4 U x2=(5+√17)/4
x≤(5-√17)/4 U x≥(5+√17)/4
x²-2x-1≥0
D=4+4=8
x3=(2-2√2)/2=1-√2 U x4=1+√2
x≤1-√2 U x≥1+√2
2x²-5x+1-x²+2x+1<0
x²-3x+2<0
x5+x6=3 U x5*x6=2⇒x5=1 U x6=2
1<x<2
x∈[1+√2;2)