若√x=√a-[1/√a] 求x+2+[√4x+x^2]/x+2-[√4x+x^2]

问题描述:

若√x=√a-[1/√a] 求x+2+[√4x+x^2]/x+2-[√4x+x^2]
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√x=√a- 1/√a平方得x=a+1/a-2x+2=a+1/ax+4=a+1/a+2所以4x+x²=x(x+4)=(a+1/a-2)(a+1/a+2)=(a+1/a)²-2²=a²+2+1/a²-4=a²-2+1/a²=(a-1/a)²因为√x=√a-1/√a≥0所以a-1/a≥0x...