仅列出我的方法,标准方法不太清楚.
设a=3-√5 b=3+√5
则x=√a-√b
则x^2=(√a-√b)^2
=a+b-2√(ab)
=6-2√[(3-√5)*(3+√5)]
=6-2√[3^2-(√5)^2]
=6-2√4
=6-4
=2
则x=±√2
因为a
仅列出我的方法,标准方法不太清楚.
设a=3-√5 b=3+√5
则x=√a-√b
则x^2=(√a-√b)^2
=a+b-2√(ab)
=6-2√[(3-√5)*(3+√5)]
=6-2√[3^2-(√5)^2]
=6-2√4
=6-4
=2
则x=±√2
因为a