103 x 103 + 97 x 97 =?
(A) 21348
(B) 20018
(C) 19648
(D) 21428答案: (B)
解释:
103 x 103 + 97 x 97
= (100+3)2 + (100-3)2
= 2 (1002 + 32 )
[ (X +Y)2 + ( X – Y)2 = 2 ( X2 + Y2 ) ]
= 2 (10000 + 9 )
= 2 x 10009
= 20018
这个问题的测验
📅  最后修改于: 2021-05-13 22:16:04             🧑  作者: Mango
103 x 103 + 97 x 97 =?
(A) 21348
(B) 20018
(C) 19648
(D) 21428答案: (B)
解释:
103 x 103 + 97 x 97
= (100+3)2 + (100-3)2
= 2 (1002 + 32 )
[ (X +Y)2 + ( X – Y)2 = 2 ( X2 + Y2 ) ]
= 2 (10000 + 9 )
= 2 x 10009
= 20018
这个问题的测验