7 tháng 6 2022 lúc 14:30
Tuyển Cộng tác viên Hoc24 nhiệm kì 26 tại đây: https://forms.gle/dK3zGK3LHFrgvTkJ6
Chương I : Ôn tập và bổ túc về số tự nhiên
Các câu hỏi tương tự
So sánh A; B; C biết
A = \(\left(-\dfrac{43}{51}\right).\left(-\dfrac{19}{80}\right)\)
B = \(\left(-\dfrac{7}{13}\right).\left(-\dfrac{4}{65}\right).\left(-\dfrac{8}{31}\right)\)
C = \(\dfrac{-5}{10}.\dfrac{-4}{10}.\dfrac{-3}{10}...\dfrac{3}{10}.\dfrac{4}{10}.\dfrac{5}{10}\)
1 .Tìm x biết
a. ( dfrac{1}{1.4}+dfrac{1}{4.7}+dfrac{1}{7.10}+...+dfrac{1}{97.100}) dfrac{0,33x}{2009}
b. 1 + dfrac{1}{3}+dfrac{1}{6}+dfrac{1}{10}+...+dfrac{2}{xleft(x+1right)}1dfrac{1991}{1993}
c. dfrac{1}{2013}x+1+dfrac{1}{2}+dfrac{1}{6}+dfrac{1}{12}+...+dfrac{1}{2012.2013}2
d. 2x + dfrac{7}{6}+dfrac{13}{12}+dfrac{21}{20}+dfrac{31}{30}+dfrac{43}{42}+dfrac{57}{56}+dfrac{73}{72}+dfrac{91}{90}10
2. Chứng minh rằng :
a. dfrac{1}{4}+dfrac{1}{4^2}+dfrac{1}{4^3}+...+dfrac{1}{4^{99}} dfrac{1}{3...
Đọc tiếp
1 .Tìm x biết
a. ( \(\dfrac{1}{1.4}+\dfrac{1}{4.7}+\dfrac{1}{7.10}+...+\dfrac{1}{97.100}\)) = \(\dfrac{0,33x}{2009}\)
b. 1 + \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x\left(x+1\right)}=1\dfrac{1991}{1993}\)
c. \(\dfrac{1}{2013}x+1+\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+...+\dfrac{1}{2012.2013}=2\)
d. 2x + \(\dfrac{7}{6}+\dfrac{13}{12}+\dfrac{21}{20}+\dfrac{31}{30}+\dfrac{43}{42}+\dfrac{57}{56}+\dfrac{73}{72}+\dfrac{91}{90}=10\)
2. Chứng minh rằng :
a. \(\dfrac{1}{4}+\dfrac{1}{4^2}+\dfrac{1}{4^3}+...+\dfrac{1}{4^{99}}< \dfrac{1}{3}\)
b. \(\dfrac{1}{1.2.3}+\dfrac{1}{2.3.4}+...+\dfrac{1}{18.19.20}< \dfrac{1}{4}\)
1) Tìm x biết:
\(\left(1-\dfrac{3}{10}-x\right):\left(\dfrac{19}{10}-1-\dfrac{2}{5}\right)+\dfrac{4}{5}=1\)
2) Tính nhanh
a)\(\dfrac{1}{1.2.3}+\dfrac{1}{2.3.4}+\dfrac{1}{3.4.5}+...+\dfrac{1}{10.11.12}\)
b)\(\dfrac{1^2}{1.2}.\dfrac{2^2}{2.3}.\dfrac{3^2}{3.4}.\dfrac{4^2}{4.5}\)
\(\dfrac{6:\dfrac{3}{5}-1\dfrac{1}{6}x\dfrac{6}{7}}{\dfrac{4}{5}x\dfrac{10}{11}+5\dfrac{2}{12}}\)
Tìm x biết
\(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{2011}{2013}\)
Rút gọn
a,\(\dfrac{3^{10}.\left(-5\right)^{21}}{\left(-5\right)^{20}.3^{12}}\)
b,\(\dfrac{-11^5.13^7}{11^5.13^8}\)
c, \(\dfrac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}\)
Tính ( bằng cách thuận tiên nếu có thể )
a, A dfrac{3^2}{10}+dfrac{3^2}{40}+dfrac{3^2}{8^8}+...+dfrac{3^2}{340}
b, A dfrac{5^2}{1cdot6}+dfrac{5^2}{6cdot11}+...+dfrac{5^2}{26cdot31}
c, A dfrac{1}{2}+dfrac{2}{2cdot4}+dfrac{3}{4cdot7}+dfrac{4}{7cdot11}+dfrac{5}{11cdot16}
d, A dfrac{3}{54}+dfrac{5}{126}+dfrac{7}{249}+dfrac{8}{609}
e, A dfrac{2}{3}+dfrac{14}{15}+dfrac{34}{35}+dfrac{62}{63}
Đọc tiếp
Tính ( bằng cách thuận tiên nếu có thể )
a, A = \(\dfrac{3^2}{10}\)+\(\dfrac{3^2}{40}\)+\(\dfrac{3^2}{8^8}\)+...+\(\dfrac{3^2}{340}\)
b, A = \(\dfrac{5^2}{1\cdot6}\)+\(\dfrac{5^2}{6\cdot11}\)+...+\(\dfrac{5^2}{26\cdot31}\)
c, A = \(\dfrac{1}{2}\)+\(\dfrac{2}{2\cdot4}\)+\(\dfrac{3}{4\cdot7}\)+\(\dfrac{4}{7\cdot11}\)+\(\dfrac{5}{11\cdot16}\)
d, A = \(\dfrac{3}{54}+\dfrac{5}{126}+\dfrac{7}{249}+\dfrac{8}{609}\)
e, A = \(\dfrac{2}{3}+\dfrac{14}{15}+\dfrac{34}{35}+\dfrac{62}{63}\)
N=\(\dfrac{1}{10^2}+\dfrac{1}{11^2}+\dfrac{1}{12^2}+...+\dfrac{1}{n^2}\)
Chứng minh rằng: N<\(\dfrac{1}{9}\)
\(x:\dfrac{-3}{5}=\dfrac{-10}{21}\)
tính
G dfrac{1}{2}+ dfrac{1}{2^2}+dfrac{1}{2^3}+...+dfrac{1}{2^5}
Qdfrac{1}{2}+dfrac{1}{2^2}+dfrac{1}{2^3}+...+ dfrac{1}{2^{10}}
m.n giúp e vs nhé! trình bày rõ ràng nha^^ cảm ơn nhiều ạ 3
Đọc tiếp
tính
G= \(\dfrac{1}{2}\)+ \(\dfrac{1}{2^2}\)+\(\dfrac{1}{2^3}\)+...+\(\dfrac{1}{2^5}\)
Q=\(\dfrac{1}{2}\)+\(\dfrac{1}{2^2}\)+\(\dfrac{1}{2^3}\)+...+ \(\dfrac{1}{2^{10}}\)
m.n giúp e vs nhé\! trình bày rõ ràng nha^^ cảm ơn nhiều ạ <3