1 tinh
a,\(5\dfrac{4}{23}.27\dfrac{3}{47}+4\dfrac{3}{47}.\left(-5\dfrac{4}{23}\right)\)
b,4.\(\left(\dfrac{-1}{2}\right)^3+\dfrac{3}{2}\)
c,\(\left(\dfrac{1999}{2011}-\dfrac{2011}{1999}\right)-\left(\dfrac{-12}{1999}-\dfrac{12}{2011}\right)\)
d,\(\left(\dfrac{-5}{11}+\dfrac{7}{22}-\dfrac{-4}{33}-\dfrac{5}{44}\right):\left(\dfrac{381}{22}-39\dfrac{7}{22}\right)\)
Tính \(\dfrac{P}{Q}\) biết:
P= \(\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2012}\)
Q= \(\dfrac{1}{2011}+\dfrac{2}{2010}+\dfrac{3}{2009}+...+\dfrac{2010}{2}+\dfrac{2011}{1}\)
So sánh A và B:
1. A=\(\dfrac{79^{2011} - 5}{79^{2011} + 8}\) và B=\(\dfrac{79^{2012} - 6}{79^{2011} + 7}\)
2. A=\(\dfrac{43}{2011^{2012}}\)+\(\dfrac{79}{2011^{2013}}\) và B=\(\dfrac{79}{2011^{2012}}\)+\(\dfrac{43}{2011^{2013}}\)
3. A=\(\dfrac{2010}{2011}\):\(\dfrac{2011}{2012}\) và B=\(\dfrac{2010+2011}{2011+2012}\)
4. A=\(\dfrac{n}{2n+1}\) và B=\(\dfrac{3n+1}{6n+3}\)
Thanks mấy bạn trước nha!!
1,So sánh :
A=\(\dfrac{2011+2012}{2012+2013}\) ; B=\(\dfrac{2011}{2012}+\dfrac{2012}{2013}\)
2,Cmr:
\(\dfrac{1}{4.7}+\dfrac{1}{7.10}+...+\dfrac{1}{37.40}< \dfrac{1}{3}\)
so sánh
a/ 55553 với 44444 b/ \(A=\dfrac{2011^{2012}+4}{2011^{2012}-1}với,,,,,,B=\dfrac{2011^{2012}_{ }+1}{2011^{2012}-4}\)
Bài 1: Tính hợp lý:
a. 1152 - (374 + 1152) + (374 - 65)
b. \(\dfrac{7}{12}\) + \(\dfrac{5}{6}\) + \(\dfrac{1}{4}\) - \(\dfrac{3}{7}\) - \(\dfrac{5}{12}\)
c. \(\dfrac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}\)
d, \(\dfrac{3}{2^2}\) . \(\dfrac{8}{3^2}\) . \(\dfrac{15}{4^2}\) ... \(\dfrac{899}{30^2}\)
Bài 2: Tìm x biết:
a, 2x + 2x+1 + 2x+2 + 2 x+3 = 480
b, \(\left(\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2012}+\dfrac{1}{2013}\right)\) . x = \(\dfrac{2012}{1}+\dfrac{2011}{2}+\dfrac{2010}{3}+...+\dfrac{2}{2011}+\dfrac{1}{2012}.\)
Bài 1. Chứng tỏ rằng: B=\(\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+\dfrac{1}{5^2}+\dfrac{1}{6^2}+\dfrac{1}{7^2}+\dfrac{1}{8^2}< 1\)
Bài 2. so sánh : A=\(\dfrac{2011+2012}{2012+2013}\)
và B=\(\dfrac{2011}{2012}+\dfrac{2012}{2013}\)
Bài 3. Rút gọn : B= \(\left(1-\dfrac{1}{1}\right).\left(1-\dfrac{1}{3}\right).\left(1-\dfrac{1}{4}\right)...\left(1-\dfrac{1}{20}\right)\)
Bài 4. Rút gọn biểu thức : A= \(1+\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{2012}}\)
Bài 5. Tìm số nguyên \(\pi\) sao cho \(\pi+5\) chia hết cho \(\pi-2\)
HELP ME!!!! MÌNH TICK CHO HA
Tìm x:
\(\dfrac{x+1}{2011}+\dfrac{x+2}{2010}+\dfrac{x+3}{2009}+\dfrac{x+4}{2008}=-4\)
\(\dfrac{298}{719}:\left(\dfrac{1}{4}+\dfrac{1}{12}-\dfrac{1}{3}\right)-\dfrac{2011}{2012}\)