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x^2=(x+1)^2+1-2(x+1)
x^2-2(x+1)=(x+1)^2+1>0
x^2>2(x+1)>x/2
(x+1)>2√x
x/2+1/2>=√x
x/2>=√x-1/2
x^2>√x-1/2