Câu hỏi của Dương Hoàng Hiếu

Question

5

+

5

+ … +

5

=

10 Phạm Công Danh · Accepted Answer

Heo lo kit tiCâu trả lời: Heo lo kit ti

Nguyễn Huy Tú · Answer

$\dfrac{5}{2}\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+...+\dfrac{1}{142}-\dfrac{1}{144}\right)$

$=\dfrac{5}{2}\left(\dfrac{1}{2}-\dfrac{1}{144}\right)=\dfrac{355}{288}$

Câu trả lời:

$\dfrac{5}{2}\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+...+\dfrac{1}{142}-\dfrac{1}{144}\right)$

$=\dfrac{5}{2}\left(\dfrac{1}{2}-\dfrac{1}{144}\right)=\dfrac{355}{288}$

5	+	5	+ … +	5	=
2 x 4	+	4 x 6	+ … +	142 x 144	=

5	+	5	+ … +	5	=
8 x 9	9 x 10	85 x 86

4	+	4	+ … +	4	=
7 x 9	9 x 11	195 x 197

35 x 24	=	24 x	=	24	x	35	= x 7 =
6 x 5	6 x 5		5