问题
选择题
已知:a=
|
答案
∵a=
=
+310 (
-3)(10
+3)10
+3,10
b=
=
-310 (
+3)(10
-3)10
-3;10
∴
=a2+b2-2
=(a-b)2+2ab-2
=6.36+2-2
故选B.
已知:a=
|
∵a=
=
+310 (
-3)(10
+3)10
+3,10
b=
=
-310 (
+3)(10
-3)10
-3;10
∴
=a2+b2-2
=(a-b)2+2ab-2
=6.36+2-2
故选B.