Ôn tập toán 6
Các câu hỏi tương tự
bài nâng cao, mn giúp mk nha:
Cho P = \(\dfrac{3}{\left(1\cdot2\right)^2}+\dfrac{5}{\left(2\cdot3\right)^2}+\dfrac{7}{\left(2.3\right)^2}+...+\dfrac{4033}{\left(2016\cdot2017\right)^2}\)
CMR: P < 1
\(\left(1\cdot3\cdot5\cdot...\cdot2017-2\cdot4\cdot6\cdot...\cdot100\right)\)không chia hết cho 2
Tính tổng :
a) Afrac{5}{2cdot1}+frac{4}{1cdot11}+frac{3}{11cdot14}+frac{1}{14cdot15}+frac{13}{15cdot28}
b) Bfrac{-1}{20}+frac{-1}{30}+frac{-1}{42}+frac{-1}{56}+frac{-1}{72}+frac{-1}{90}
c) Cfrac{1}{1cdot2cdot3}+frac{1}{2cdot3cdot4}+...+frac{1}{nleft(n+1right)left(n+2right)}
d) Dfrac{1}{1cdot2cdot3cdot4}+frac{1}{2cdot3cdot4cdot5}+...+frac{1}{nleft(n+1right)left(n+2right)left(n+3right)}
e) Eleft(frac{1}{1cdot2cdot3}+frac{1}{2cdot3cdot4}+...+frac{1}{37cdot38cdot39}right)cdot1482cdot185cdot8
Đọc tiếp
Tính tổng :
a) \(A=\frac{5}{2\cdot1}+\frac{4}{1\cdot11}+\frac{3}{11\cdot14}+\frac{1}{14\cdot15}+\frac{13}{15\cdot28}\)
b) \(B=\frac{-1}{20}+\frac{-1}{30}+\frac{-1}{42}+\frac{-1}{56}+\frac{-1}{72}+\frac{-1}{90}\)
c) \(C=\frac{1}{1\cdot2\cdot3}+\frac{1}{2\cdot3\cdot4}+...+\frac{1}{n\left(n+1\right)\left(n+2\right)}\)
d) \(D=\frac{1}{1\cdot2\cdot3\cdot4}+\frac{1}{2\cdot3\cdot4\cdot5}+...+\frac{1}{n\left(n+1\right)\left(n+2\right)\left(n+3\right)}\)
e) \(E=\left(\frac{1}{1\cdot2\cdot3}+\frac{1}{2\cdot3\cdot4}+...+\frac{1}{37\cdot38\cdot39}\right)\cdot1482\cdot185\cdot8\)
tính tổng
Sdfrac{1}{1cdot2cdot3}+dfrac{1}{2cdot3cdot4}+dfrac{1}{3cdot4cdot5}+...+dfrac{1}{ncdotleft(n+1right)cdotleft(n+2right)}
A1+dfrac{1}{3}+dfrac{1}{5}+dfrac{1}{7}+...+dfrac{1}{99}
B dfrac{1}{2}+dfrac{1}{3}+dfrac{1}{4}+...dfrac{1}{100}
Cdfrac{99}{1}+dfrac{98}{2}+dfrac{97}{3}+...+dfrac{1}{99}
Đọc tiếp
tính tổng
S=\(\dfrac{1}{1\cdot2\cdot3}+\dfrac{1}{2\cdot3\cdot4}+\dfrac{1}{3\cdot4\cdot5}+...+\dfrac{1}{n\cdot\left(n+1\right)\cdot\left(n+2\right)}\)
A=1+\(\dfrac{1}{3}+\dfrac{1}{5}+\dfrac{1}{7}+...+\dfrac{1}{99}\)
B= \(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...\dfrac{1}{100}\)
C=\(\dfrac{99}{1}+\dfrac{98}{2}+\dfrac{97}{3}+...+\dfrac{1}{99}\)
\(\dfrac{-5}{9}+1\dfrac{5}{9}\cdot\left(\dfrac{3}{4}-\dfrac{2}{5}\right):7^2\)
\(1\dfrac{13}{15}\cdot0,75-\left(\dfrac{104}{195}+25\%\right)\cdot\dfrac{24}{47}-3\dfrac{12}{13}:3\)
\(1\dfrac{13}{15}\cdot\left(0,5\right)^2\cdot3+\left(\dfrac{8}{15}+1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
Tính tổng :
a) \(C=1\cdot2+2\cdot3+...+100\cdot101\)
b) \(A=1\cdot2+2\cdot3+...+n\left(n+1\right)\)
a) Tìm số tự nhiên x biết : \(\left(\dfrac{1}{1\cdot2\cdot3}+\dfrac{1}{2\cdot3\cdot4}+...+\dfrac{1}{8\cdot9\cdot10}\right)\cdot x=\dfrac{23}{45}\)
b) Tìm các số tự nhiên a ; b; c ; d biết : \(\dfrac{30}{43}=\dfrac{1}{a+\dfrac{1}{b+\dfrac{1}{c+\dfrac{1}{d}}}}\)
Bài 1:Tính
a, Adfrac{3}{4}cdotdfrac{8}{9}cdotdfrac{15}{16}cdot....cdotdfrac{9999}{10000}
b,Bleft(1-dfrac{1}{21}right)cdotleft(1-dfrac{1}{28}right)cdotleft(1-dfrac{1}{36}right)cdot....cdotleft(1-dfrac{1}{1326}right)
c,Cleft(1+dfrac{1}{1cdot3}right)cdotleft(1+dfrac{1}{2cdot4}right)cdotleft(1+dfrac{1}{3cdot5}right)cdot....cdotleft(1+dfrac{1}{99cdot101}right)
Đọc tiếp
Bài 1:Tính
a, A=\(\dfrac{3}{4}\cdot\dfrac{8}{9}\cdot\dfrac{15}{16}\cdot....\cdot\dfrac{9999}{10000}\)
b,B=\(\left(1-\dfrac{1}{21}\right)\cdot\left(1-\dfrac{1}{28}\right)\cdot\left(1-\dfrac{1}{36}\right)\cdot....\cdot\left(1-\dfrac{1}{1326}\right)\)
c,C=\(\left(1+\dfrac{1}{1\cdot3}\right)\cdot\left(1+\dfrac{1}{2\cdot4}\right)\cdot\left(1+\dfrac{1}{3\cdot5}\right)\cdot....\cdot\left(1+\dfrac{1}{99\cdot101}\right)\)
Tìm x
a ) \(15-3\cdot x=6\) b)\(\dfrac{2}{3}-\dfrac{4}{3}\cdot x=\dfrac{1}{2}\) c) \(3^{19}\cdot\left(x-12\right)=4\cdot3^{20}\) d) \(3\cdot\left(x-4\right)=2^2\cdot3^3\)