根号(x减x分之1)的平方加4减根号(x加x分之1)的平方减4
√[(x-1/x)²+4]-√[(x+1/x)²-4]
=√(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]
因为0
根号(x减x分之1)的平方加4减根号(x加x分之1)的平方减4
√[(x-1/x)²+4]-√[(x+1/x)²-4]
=√(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]
因为0