(x+1/2)2+(x−1/2)2+(x+1/2)(x−1/2).

问题描述:

(x+

1
2
)2+(x−
1
2
)2+(x+
1
2
)(x−
1
2
).

原式=x2+x+

1
4
+x2-x+
1
4
+x2-
1
4
=3x2+
1
4