√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<br>x²-3x+2<0<br>x5+x6=3 U x5*x6=2⇒x5=1 U x6=2 1x∈[1+√2;2)