已知x=(1-√5)/2,则1/x=(-1-√5)/2,
所以x+1/x=(1-√5-1-√5)/2=-√5,
x-1/x=(1-√5+1+√5)/2=1；
故√(x³-1/x³)
=√(x-1/x)×(x²+1+1/x²)
=√(x-1/x)[(x+1/x)²-1]
=√1×(5-1)
=√4
=2
设x=(1-√5)÷2则√(x3-1÷x3)
已知x=(1-√5)/2,则1/x=(-1-√5)/2,
所以x+1/x=(1-√5-1-√5)/2=-√5,
x-1/x=(1-√5+1+√5)/2=1；
故√(x³-1/x³)
=√(x-1/x)×(x²+1+1/x²)
=√(x-1/x)[(x+1/x)²-1]
=√1×(5-1)
=√4
=2