问题 填空题
已知:a+
1
a
=3,则a2+
1
a2
=______;a-
1
a
=______.
答案

∵a+

1
a
=3,a2+
1
a2
=(a+
1
a
2-2,

∴原式=32-2=7,

∵(a-

1
a
2=(a+
1
a
2-4=9-4=5,

∴±

5

故答案为:7,±

5

单项选择题 A1/A2型题
名词解释