請問這一題我該怎麼解?
回答 (1)
2018-03-23 2:04 am
該長方形垛共有柳丁 12×6+11×5+10×4+9×3+8×2+7×1
= (6+6)6+(6+5)5+(6+4)4+(6+3)3
+(6+2)2+(6+1)1
=6(6+5+4+3+2+1)
+ 6^2+5^2+4^2+3^2+2^2+1^2
=6(6×7)/2 + 6×7×(2×6+1)/6
=126 + 91
= 217個
= (6+6)6+(6+5)5+(6+4)4+(6+3)3
+(6+2)2+(6+1)1
=6(6+5+4+3+2+1)
+ 6^2+5^2+4^2+3^2+2^2+1^2
=6(6×7)/2 + 6×7×(2×6+1)/6
=126 + 91
= 217個
收錄日期: 2021-04-11 21:46:55
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20180321144649AAhFe8X