已知0已知0
已知0原式=√(x²-2+1/x²+4)-√(x²+2+1/x²-4)=√(x²+2+1/x²)-√(x²-2+1/x²)=√(x+1/x)²-√(x-1/x)²=|x+1/x|-|x-1/x|0