so sánh A=2011/1.2 +2011/3.4+2011/5.6 +..........+2011/1999.2000
B=2012/1001+2012/1002+.........+2012/2000
giúp vs các bn
B=\(\dfrac{2011}{1.2}+\dfrac{2011}{3.4}+\dfrac{2011}{5.6}+...+\dfrac{2011}{1999.2000}\)
hãy tính B giúp mk nhé
so sánh A và B biết \(A=\dfrac{2011}{\sqrt{2012}}+\dfrac{2012}{\sqrt{2011}}vàB=\sqrt{2011}+\sqrt{2012}\)
P=\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{2012}}{\dfrac{2011}{1}+\dfrac{2010}{2}+\dfrac{2009}{3}+...+\dfrac{1}{2011}}\)
\(A=1-\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}+.........+\dfrac{1}{2011}-\dfrac{1}{2012}+\dfrac{1}{2013}\)
\(B=\dfrac{1}{1007}+\dfrac{1}{1008}+\dfrac{1}{1009}+.........+\dfrac{1}{2013}\)
tính \(\left(A-B\right)^{2013}\)
Cho \(\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}=\dfrac{d}{a}\). Tính\(\dfrac{a^{20}.b^{11}.c^{2011}}{d^{2042}}\)
Tìm x:
\(\left(\dfrac{1}{2}+\dfrac{1}{3}+.....+\dfrac{1}{2014}\right)x=\dfrac{2013}{1}+\dfrac{2012}{2}+.....+\dfrac{2}{2012}+\dfrac{1}{2013}\)
1)
a) So sánh (-99)20 và 9999100
b) Chứng tỏ A = 2720 + 361 + 931 chia hết cho 13
2)
Cho\(\dfrac{a}{b}\)= \(\dfrac{b}{c}\)=\(\dfrac{c}{2011}\) =\(\dfrac{2011}{a}\) và a+b+c khác 0. Tính a+b-c
3) Tính M = \(\dfrac{4}{237}-\dfrac{4}{2371}+\dfrac{4}{23711}\) phần \(\dfrac{-5}{237}+\dfrac{5}{2371}-\dfrac{5}{23711}\)
Tìm \(n\in Z\) để A = \(1:\left(\dfrac{1}{2011}-\dfrac{1}{2011+n}\right)\) có giá trị nguyên