问题
填空题
设x=
|
答案
∵x=
=1
-12
+1,而2<2
+1<3,2
∴a=x-2=
-1.2
又∵-x=-
-1,而-3<-2
-1<-2,2
∴b=-
-1+3=2-2
.2
∴a+b=1,
∴a3+b3+3ab=(a+b)(a2-ab+b2)+3ab
=(a2-ab+b2)+3ab
=a2+2ab+b2
=(a+b)2
=1,
故答案为:1.
设x=
|
∵x=
=1
-12
+1,而2<2
+1<3,2
∴a=x-2=
-1.2
又∵-x=-
-1,而-3<-2
-1<-2,2
∴b=-
-1+3=2-2
.2
∴a+b=1,
∴a3+b3+3ab=(a+b)(a2-ab+b2)+3ab
=(a2-ab+b2)+3ab
=a2+2ab+b2
=(a+b)2
=1,
故答案为:1.