Tính A=(1+1/1.3)(1+1/2.4)(1+1/3.5)..........(1+1/2007.2009)
tra loi chi tiet minh tick cho
Tinh phan so sau:
1/3 x 1/2 - 1/5 x 1/2 (giai chi tiet)
giup minh voi, tra loi minh tick cho nha
\(\dfrac{1}{2}\times\left(\dfrac{1}{3}-\dfrac{1}{5}\right)=\dfrac{1}{2}\times\left(\dfrac{5}{15}-\dfrac{3}{15}\right)=\dfrac{1}{2}\times\dfrac{2}{15}=\dfrac{1}{15}\)
Tính A=(1+1/1.3)(1+1/2.4)(1+1/3+5)......(1+1/2007.2009)
a) 1/1.3+1/3.5+1/5.7
b) 1/1.3+1/3.5+1/5.7+...+1/2007.2009+1/2009.2011
a)\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}\)
\(=\frac{1}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}\right)\)
\(=\frac{1}{2}.\left(1-\frac{1}{7}\right)\)
\(=\frac{1}{2}.\frac{6}{7}\)
\(=\frac{3}{7}\)
b)\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2007.2009}+\frac{1}{2009.2011}\)
\(=\frac{1}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{2009}-\frac{1}{2011}\right)\)
\(=\frac{1}{2}.\left(1-\frac{1}{2011}\right)\)
\(=\frac{1}{2}.\frac{2010}{2011}\)
\(=\frac{1005}{2011}\)
Kết quả phép tính: 1/1.3+1/3.5+1/5.7+...+1/2007.2009 help mik vs
\(=\dfrac{1}{2}\left(1-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+...+\dfrac{1}{2007}-\dfrac{1}{2009}\right)=\dfrac{1}{2}\cdot\dfrac{2008}{2009}=\dfrac{1004}{2009}\)
Cho A = ( 1 + 1/1.3 ) ( 1 + 1/2.4 ) ( 1 + 1/3.5 ) .... ( 1 + 1/2017/2019 )
Chứng minh A > 2
Kết quả phép tính: 1/1.3+1/3.5+1/5.7+...+1/2007.2009+1/2009.2011. Giải thích hộ mình nhé
= 1/2 . (1/1 - 1/3 + 1/3 - 1/5 +... + 1/2009 - 1/2011)
= 1/2 . (1/1 - 1/2011)
= 1/2 . 2010 / 2011
= 1005/2011
1/2 ( 2/1.3 + 2/3.5 +...+ 2 /2009.2011)
= 1/2 ( 1/1 - 1/3 + 1/3 - 1/5 +... + 1/2009 - 1/2011)
= 1/2( 1/1 - 1/2011)
= 1/2 . 2010 / 2011
=1005/2011
Tính: A=(1-\(\frac{1}{1.3}\)).(1-\(\frac{1}{2.4}\)).(1-\(\frac{1}{3.5}\))...(1-\(\frac{1}{98.100}\))
Giúp mk nhé mn. Mk đang cần gấp.Nhớ giải chi tiết nhé. Mk tick cho.
1/1.3+1/3.5+1/5.7+...+1/2007.2009+1/2009.2010
2A = 2/1.3 +2/3.5 + 2/5.7 + ... + 2/2007.2009 + 2/2009. 2011
2A = 1/1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + ... + 1/ 2007 - 1/2009 + 1/2009 - 1/2011
Gian uoc het ta co: 2A = 1/1 - 1/2011
2A = 2010/2011
A = 2010/2011 X 1/2
A = 1005/2011
**** mình nha
Tính tổng S=1/1.3+1/2.4+1/3.5+.....+1/4.9+1/8.10
Ai giải giúp mik đi mik phải làm bài kiểm tra để nộp cô.
S =\(\frac{1}{2}\left(1-\frac{1}{3}\right)+\frac{1}{2}\left(\frac{1}{2}-\frac{1}{4}\right)+....\frac{1}{2}\left(\frac{1}{8}-\frac{1}{10}\right)\)
S = 1/2 ( 1 -1/3 +1/2-1/4+......+ 1/8-1/10)
S = 1/2(1+1/2-1/9-1/10)
S= 29/45
Bạn nói cô giáo sửa đề thành:
Tính tổng S=1/1.3+1/2.4+1/3.5+.....+1/\(7\).9+1/8.10
chứ không tổng S lẻ lắm, chẳng ai muốn tính cả.