问题
解答题
观察规律并填空(本题7分) (1)(2+
(3+
(4+
(2)若(x+
|
答案
(1)由(2+
)2=22+2+1 2
和(3+1 22
)2=32+2+1 3
得:(4+1 32
)2=42+2+1 4
.1 42
(2)由(1)中等式可以得到规律:(x+
)2=x2+2+1 x
;1 x2
∵(x+
)2=13;1 x
∴(x+
)2=x2+2+1 x
=13;1 x2
解得x2+
=13-2=11.1 x2