giúp mik với, t4 mik đi hc rùi
\(\left(1+\frac{1}{1.3}\right)\left(1+\frac{1}{2.4}\right)\left(1+\frac{1}{3.5}\right).......\left(1+\frac{1}{2014.2016}\right)=\frac{x}{1008}\)
\(A=\left(1+\frac{1}{1.3}\right).\left(1+\frac{1}{3.5}\right).\left(1+\frac{1}{5.7}\right).....\left(1+\frac{1}{2015.2017}\right)\)
Tính A
tính tổng:
I=\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{\left(2n+1\right).\left(2n+3\right)}\)
Bài 1: Thực hiện phép tính 1 cách hợp lý :
\(a\)) \(\left(1+\frac{1}{1.3}\right).\left(1+\frac{1}{2.4}\right).\left(1+\frac{1}{3.5}\right)...\left(1+\frac{1}{2009.2011}\right)\)
\(b\)) \(\frac{16}{9}-\frac{1}{36}-\frac{1}{28}-\frac{1}{21}-\frac{1}{15}-\frac{1}{10}-\frac{1}{6}-\frac{1}{3}-1\)
\(c\)) \(\frac{0,4-\frac{2}{9}+\frac{2}{11}-\frac{2}{37}}{1,4-\frac{7}{9}-\frac{7}{11}-\frac{7}{37}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,785+0,7}\)
Tính:
\(M=\frac{\left(1+17\right)\left(1+\frac{17}{2}\right)\left(1+\frac{17}{3}\right)........\left(1+\frac{17}{19}\right)}{\left(1+19\right)\left(1+\frac{19}{2}\right)\left(1+\frac{19}{3}\right)........\left(1+\frac{19}{17}\right)}\)
Tính nhanh:
A = \(\left(\frac{1}{4}-1\right).\left(\frac{1}{9}-1\right).\left(\frac{1}{16}-1\right).\left(\frac{1}{25}-1\right).....\left(\frac{1}{121}-1\right)\)
HELP ME
Tính: \(S=\left(\frac{1}{4}-1\right).\left(\frac{1}{9}-1\right).\left(\frac{1}{16}-1\right).....\left(\frac{1}{81}-1\right).\left(\frac{1}{100}-1\right)\)
Tính A = \(\left(1+\dfrac{1}{1.3}\right)\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)....\left(1+\dfrac{1}{99.101}\right)\)
Tính :
a ) \(\left(\frac{1}{2}+1\right).\left(\frac{1}{3}+1\right)...\left(\frac{1}{99}+1\right)\)
b )\(\left(\frac{1}{2}-1\right).\left(\frac{1}{3}-1\right)...\left(\frac{1}{100}-1\right)\)
c ) \(\frac{3}{2^2}.\frac{8}{3^2}.\frac{15}{4^2}...\frac{899}{30^2}\)