\(A=\left(1-\frac{1}{2010}\right).\left(1-\frac{2}{2010}\right).\left(1-\frac{3}{2010}\right)....\left(1-\frac{2011}{2010}\right)\)
1.tính tổng
a. A=\(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right).....\left(1-\frac{1}{20}\right)\)
b. B=\(\left(1-\frac{1}{2010}\right).\left(1-\frac{2}{2010}\right).\left(1-\frac{3}{2010}\right).....\left(1-\frac{2011}{2010}\right)\)
a)\(A=\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)\left(1-\frac{1}{5}\right)...\left(1-\frac{1}{20}\right)\)
\(A=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}...\frac{19}{20}\)
\(A=\frac{1.2.3...19}{2.3.4...20}\)
\(A=\frac{1}{20}\)
Tính tich : \(A=\left(1-\frac{1}{2010}\right).\left(1-\frac{2}{2010}\right).\left(1-\frac{3}{2010}\right)......\left(1-\frac{2011}{2010}\right)\)
trong dãy tích A sẽ có phân số \(1-\frac{2010}{2010}=1-1=0\)
=>A=0
\(A=\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right).........\left(1-\frac{2010}{2010}\right)\left(1-\frac{2011}{2010}\right)\)
\(A=\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)......0.\left(1-\frac{2011}{2010}\right)\)
A = 0
Tính A= \(\left(1-\frac{1}{2010}\right).\left(1-\frac{2}{2010}\right).\left(1-\frac{3}{2010}\right)....\left(1-\frac{2011}{2010}\right)\)
\(A=\frac{ }{ }sdadsad\text{đ}\text{s}gh\text{d}fg\text{d}\)sf
Tính: \(A=\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)\left(1-\frac{3}{2010}\right)\left(1-\frac{4}{2010}\right)...\left(1-\frac{4020}{2010}\right)\)
A=(2009/2010).(2008/2010). ... . (-2010/2010)
Còn lại mình chịu
Tính tích
\(A=\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)\left(1-\frac{3}{2010}\right)...\left(1-\frac{2011}{2010}\right)\)
GIÚP MK VỚI MK ĐANG CẦN GẤP
\(A=\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)...\left(1-\frac{2010}{2010}\right)\left(1-\frac{2011}{2010}\right)\)
\(=\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)...0\left(1-\frac{2011}{2010}\right)\)
\(=0\)
\(\left(1-\frac{1}{2010}\right)\cdot\left(1-\frac{2}{2010}\right)\cdot\left(1-\frac{3}{2010}\right)\cdot....\cdot\left(1-\frac{2012}{2010}\right)\)
\(1-\frac{2010}{2010}=0\Rightarrow\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)....\left(1-\frac{2012}{2010}\right)=0\)
\(\frac{1}{2011}.x=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{2010}\right).\left(1-\frac{1}{2011}\right)\)
\(\frac{1}{2011}.x=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{2010}\right).\left(1-\frac{1}{2011}\right)\)
\(\frac{1}{2011}.x=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{2009}{2010}.\frac{2010}{2011}\)
\(\frac{1}{2011}.x=\frac{1.2.3...2009.2010}{2.3.4...2010.2011}\)\(=\frac{1}{2011}\)
\(x=\frac{1}{2011}:\frac{1}{2011}=1\)
Vậy x=1
\(\frac{1}{2011}.x=\frac{1}{2}.\left(\frac{2}{3}\right).\left(\frac{3}{4}\right)......\left(\frac{2010}{2011}\right)\)
\(\frac{1}{2011}.x=\frac{2}{4}.\left(\frac{4}{6}\right).\left(\frac{6}{8}\right).......\left(\frac{4018}{4020}\right).\left(\frac{4020}{4022}\right)\)
\(\frac{1}{2011}.x=\frac{2.4.6.8.....4018.4020}{4.6.8.10.....4020.4022}\)
\(\frac{1}{2011}.x=\frac{2}{4022}\)
\(\Rightarrow\)\(x=\frac{2}{4022}:\frac{1}{2011}=1\)
Ai thấy đún thì ủng hộ mink nha !!!
Thanks you very much !!
Chúc các bạn luôn học giỏi !!!
Tính tích:
A = \(\left(1-\frac{1}{2010}\right)\left(1-\frac{2}{2010}\right)\left(1-\frac{3}{2010}\right)...\left(1-\frac{11}{2010}\right)\)
Giúp với!Còn quà thì tính sau nhé!
\(\left(\frac{1}{2011}+\frac{2}{2010}+\frac{3}{2009}+4\right):\left(\frac{1}{2009}+\frac{1}{2010}+\frac{1}{2011}+\frac{1}{2012}\right)\) = ?