a) = 1-1/2+1/2-1/3+...+1/99-1/100 =1 - 1/100 = 99/100
Đúng 0
Bình luận (0)
Chương I : Số hữu tỉ. Số thực
Các câu hỏi tương tự
Tính giá trị biểu thức sau:
1.Bleft(1-dfrac{1}{2}right)left(1-dfrac{1}{3}right)......left(1-dfrac{1}{n+1}right)với n thuộc N
2.Adfrac{1}{1.2}+dfrac{1}{2.3}+...+dfrac{1}{99.100}
3.C-66.left(dfrac{1}{2}-dfrac{1}{3}-dfrac{1}{11}right)+124.left(-37right)+63.left(-124right)
4.Ddfrac{7}{4}left(dfrac{33}{12}dfrac{3333}{2020}dfrac{333333}{303030}dfrac{33333333}{42424242}right)
giúp mik nhé
Đọc tiếp
Tính giá trị biểu thức sau:
1.\(B=\left(1-\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)......\left(1-\dfrac{1}{n+1}\right)\)với n thuộc N
2.\(A=\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
3.\(C=-66.\left(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{11}\right)+124.\left(-37\right)+63.\left(-124\right)\)
4.\(D=\dfrac{7}{4}\left(\dfrac{33}{12}\dfrac{3333}{2020}\dfrac{333333}{303030}\dfrac{33333333}{42424242}\right)\)
giúp mik nhé 
( dfrac{1}{5} + dfrac{5}{6} - dfrac{9}{10} ) . dfrac{3}{5} - 0,75 : 1dfrac{1}{2} - 1,25^2
xrightarrow[left(1dfrac{1}{2}right)^4.left(-3dfrac{1}{3}right)^3.left(-1right)^7]{left(-5right)^3.left(-0,9right)^2}
left(dfrac{1}{2}-dfrac{7}{13}-dfrac{1}{3}right) + left(dfrac{-6}{13}+dfrac{1}{2}+1dfrac{1}{3}right)
0,75 + dfrac{2}{5} + left(dfrac{1}{9}-1dfrac{2}{5}+dfrac{5}{4}right)
-66 . left(dfrac{1}{2}-dfrac{1}{3}+dfrac{1}{11}right) + 124 . (-37) + 63 . (-124)
Đọc tiếp
( \(\dfrac{1}{5}\) + \(\dfrac{5}{6}\) - \(\dfrac{9}{10}\) ) . \(\dfrac{3}{5}\) - 0,75 : \(1\dfrac{1}{2}\) - \(1,25^2\)
\(\xrightarrow[\left(1\dfrac{1}{2}\right)^4.\left(-3\dfrac{1}{3}\right)^3.\left(-1\right)^7]{\left(-5\right)^3.\left(-0,9\right)^2}\)
\(\left(\dfrac{1}{2}-\dfrac{7}{13}-\dfrac{1}{3}\right)\) + \(\left(\dfrac{-6}{13}+\dfrac{1}{2}+1\dfrac{1}{3}\right)\)
0,75 + \(\dfrac{2}{5}\) + \(\left(\dfrac{1}{9}-1\dfrac{2}{5}+\dfrac{5}{4}\right)\)
-66 . \(\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{11}\right)\) + 124 . (-37) + 63 . (-124)
tính
a) left[dfrac{0.8divleft(dfrac{4}{5}cdot1025right)}{0.64-1}+dfrac{left(1.08-dfrac{2}{25}right)divdfrac{4}{7}}{left(6dfrac{5}{7}-3dfrac{1}{4}right)cdot2dfrac{2}{17}}+left(1.2cdot0.5right)divdfrac{4}{5}right]
b) left(0.2right)^{-3}left[left(-dfrac{1}{5}right)^{-2}right]^{-1}+left[left(dfrac{1}{2}right)^{-3}right]^{-2}divleft(2^{-3}right)^{-1}-left(0.175right)^{-2}
c) 2+dfrac{1}{1+dfrac{1}{2+dfrac{1}{1+dfrac{1}{2}}}}
d) dfrac{1}{90}-dfrac{1}{72}-dfrac{1}{56}-dfrac{1}{42}-dfrac{1}{3}
e) l...
Đọc tiếp
tính
a) \(\left[\dfrac{0.8\div\left(\dfrac{4}{5}\cdot1025\right)}{0.64-1}+\dfrac{\left(1.08-\dfrac{2}{25}\right)\div\dfrac{4}{7}}{\left(6\dfrac{5}{7}-3\dfrac{1}{4}\right)\cdot2\dfrac{2}{17}}+\left(1.2\cdot0.5\right)\div\dfrac{4}{5}\right]\)
b) \(\left(0.2\right)^{-3}\left[\left(-\dfrac{1}{5}\right)^{-2}\right]^{-1}+\left[\left(\dfrac{1}{2}\right)^{-3}\right]^{-2}\div\left(2^{-3}\right)^{-1}-\left(0.175\right)^{-2}\)
c) \(2+\dfrac{1}{1+\dfrac{1}{2+\dfrac{1}{1+\dfrac{1}{2}}}}\)
d) \(\dfrac{1}{90}-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-\dfrac{1}{3}\)
e) \(\left(\dfrac{1}{3}\right)^{-1}-\left(-\dfrac{6}{7}\right)^0+\left(\dfrac{1}{2}\right)^2\div2\)
f) \(\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}-\dfrac{2}{7}-\dfrac{2}{13}}\cdot\dfrac{\dfrac{3}{4}-\dfrac{3}{16}-\dfrac{3}{64}-\dfrac{3}{256}}{1-\dfrac{1}{4}-\dfrac{1}{16}-\dfrac{1}{64}}+\dfrac{5}{8}\)
g) \(\dfrac{1}{-\left(2017\right)\left(-2015\right)}+\dfrac{1}{\left(-2015\right)\left(-2013\right)}+...+\dfrac{1}{\left(-3\right)\cdot\left(-1\right)}\)
h) \(\left(1-\dfrac{1}{1\cdot2}\right)+\left(1-\dfrac{1}{2\cdot3}+...+\left(1-\dfrac{1}{2017\cdot2018}\right)\right)\)
Bài 1: Thực hiện phép tính:
Aleft(-dfrac{1}{125}right)^{11}:left(dfrac{1}{5}right)^{32}
B1+dfrac{1}{3}+left(dfrac{1}{3}right)^2+....+left(dfrac{1}{3}right)^{2018}
Cdfrac{16^3cdot3^{10}+120cdot6^9}{4^6cdot3^{12}+6^{11}}
Dleft(dfrac{0.4-dfrac{2}{9}+dfrac{2}{11}}{1.4-dfrac{7}{9}+dfrac{7}{11}}-dfrac{dfrac{1}{3}-0.25+dfrac{1}{5}}{1dfrac{1}{6}-0.875+0.7}right):dfrac{2017}{2018}
Edfrac{1}{2}+dfrac{1}{6}+dfrac{1}{12}+dfrac{1}{20}+dfrac{1}{30}+dfrac{1}{42}+dfrac{1}{56}+dfrac{1}{72}
Gdfrac{left(dfra...
Đọc tiếp
Bài 1: Thực hiện phép tính:
\(A=\left(-\dfrac{1}{125}\right)^{11}:\left(\dfrac{1}{5}\right)^{32}\)
\(B=1+\dfrac{1}{3}+\left(\dfrac{1}{3}\right)^2+....+\left(\dfrac{1}{3}\right)^{2018}\)
\(C=\dfrac{16^3\cdot3^{10}+120\cdot6^9}{4^6\cdot3^{12}+6^{11}}\)
\(D=\left(\dfrac{0.4-\dfrac{2}{9}+\dfrac{2}{11}}{1.4-\dfrac{7}{9}+\dfrac{7}{11}}-\dfrac{\dfrac{1}{3}-0.25+\dfrac{1}{5}}{1\dfrac{1}{6}-0.875+0.7}\right):\dfrac{2017}{2018}\)
\(E=\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}\)
\(G=\dfrac{\left(\dfrac{2}{5}\right)^7\cdot5^7+\left(2\dfrac{1}{4}\right)^3:\left(\dfrac{3}{16}\right)^3}{512+2^7\cdot5^2}:\dfrac{\left(\dfrac{1}{2}\right)^0}{\left(-1\right)^{2017}}\)
Mn ơi giúp e với ........ Em đang cần gấp giúp e với nha!!
Thank you mn nhiều nhiều.....
a, left(18dfrac{1}{3}:sqrt{225}+8dfrac{2}{3}.sqrt{dfrac{49}{4}}right): left[left(12dfrac{1}{3}+8dfrac{6}{7}right)-dfrac{left(sqrt{7}right)^2}{left(3sqrt{2}right)^2}right]: dfrac{1704}{445}b, dfrac{1}{1.2}+dfrac{1}{2.3}+...+dfrac{1}{99.100}c, left(1-dfrac{1}{2}right)xleft(1-dfrac{1}{3}right)x.....xleft(1-dfrac{1}{n+1}right) (n ϵ N)d, -66 x left(dfrac{1}{2}-dfrac{1}{3}+dfrac{1}{11}right) + 124 x -37 + 63 x -124e, dfrac{7}{4} x left(dfrac{33}{12}+dfrac{3333}{2020}+dfrac{333333}{303030}+dfrac{33333...
Đọc tiếp
a, \(\left(18\dfrac{1}{3}:\sqrt{225}+8\dfrac{2}{3}.\sqrt{\dfrac{49}{4}}\right)\): \(\left[\left(12\dfrac{1}{3}+8\dfrac{6}{7}\right)-\dfrac{\left(\sqrt{7}\right)^2}{\left(3\sqrt{2}\right)^2}\right]\): \(\dfrac{1704}{445}\)
b, \(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+...+\(\dfrac{1}{99.100}\)
c, \(\left(1-\dfrac{1}{2}\right)\)x\(\left(1-\dfrac{1}{3}\right)\)x.....x\(\left(1-\dfrac{1}{n+1}\right)\) (n ϵ N)
d, -66 x \(\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{11}\right)\) + 124 x -37 + 63 x -124
e, \(\dfrac{7}{4}\) x \(\left(\dfrac{33}{12}+\dfrac{3333}{2020}+\dfrac{333333}{303030}+\dfrac{33333333}{42424242}\right)\)
A left(dfrac{1}{2}-1right)left(dfrac{1}{3}-1right).........left(dfrac{1}{10}-1right). So sánh A với dfrac{-1}{9}B left(dfrac{1}{4}-1right)left(dfrac{1}{9}-1right)...........left(dfrac{1}{100}-1right). So sánh B với dfrac{-11}{21}
Đọc tiếp
A= \(\left(\dfrac{1}{2}-1\right)\)\(\left(\dfrac{1}{3}-1\right)\).........\(\left(\dfrac{1}{10}-1\right)\). So sánh A với \(\dfrac{-1}{9}\)
B= \(\left(\dfrac{1}{4}-1\right)\)\(\left(\dfrac{1}{9}-1\right)\)...........\(\left(\dfrac{1}{100}-1\right)\). So sánh B với \(\dfrac{-11}{21}\)
1 tính
a, -dfrac{2}{3}-left(dfrac{-2}{5}right)-dfrac{7}{10}
b, dfrac{-5}{9}.left(dfrac{3}{10}-dfrac{2}{5}right)
c, left(dfrac{11}{24}:dfrac{55}{36}right).dfrac{10}{3}
d, left(dfrac{1}{2}-1right).left(dfrac{1}{3}-1right)...left(dfrac{1}{2017}-1right)
e,left(dfrac{2}{3}right):left(dfrac{4}{9}right)^{10}
f,left(dfrac{1}{7}right)^7.7^7
g, dfrac{left(125right)^5}{5^{15}}
2 tìm x, biết
a, dfrac{-4}{7}-xdfrac{5}{7}
b, x:left(dfrac{-3}{8}right)dfrac{1}{2}
c, dfrac{-3}{5}+dfrac{1}{4}:xdfrac{-...
Đọc tiếp
1 tính
a, \(-\dfrac{2}{3}-\left(\dfrac{-2}{5}\right)-\dfrac{7}{10}\)
b, \(\dfrac{-5}{9}.\left(\dfrac{3}{10}-\dfrac{2}{5}\right)\)
c, \(\left(\dfrac{11}{24}:\dfrac{55}{36}\right).\dfrac{10}{3}\)
d, \(\left(\dfrac{1}{2}-1\right).\left(\dfrac{1}{3}-1\right)...\left(\dfrac{1}{2017}-1\right)\)
e,\(\left(\dfrac{2}{3}\right):\left(\dfrac{4}{9}\right)^{10}\)
f,\(\left(\dfrac{1}{7}\right)^7.7^7\)
g, \(\dfrac{\left(125\right)^5}{5^{15}}\)
2 tìm x, biết
a, \(\dfrac{-4}{7}-x=\dfrac{5}{7}\)
b, \(x:\left(\dfrac{-3}{8}\right)=\dfrac{1}{2}\)
c, \(\dfrac{-3}{5}+\dfrac{1}{4}:x=\dfrac{-2}{5}\)
d, \(\left(x-\dfrac{2}{5}\right).\left(x+\dfrac{3}{7}\right)=0\)
e, \(\left(x+1\right)^5=-32\)
f, \(x-\left(1,5-7\right)=0,35\)
3 tìm số tự nhiên n biết
a, \(3^n=81\)
b, \(2^n=16\)
c, \(2.2^n=16\)
d, \(2.8^n=128\)
5 so sánh
a, \(2^{333}\) và \(3^{222}\)
b, \(\left(\dfrac{-1}{16}\right)^{100}\) và \(\left(\dfrac{-1}{2}\right)^{400}\)
Thu gọn các biểu thức sau
A left(-2right).left(-1dfrac{1}{2}right).left(-1dfrac{1}{3}right).left(-1dfrac{1}{4}right)...left(-1dfrac{1}{214}right)
B left(-1dfrac{1}{2}right).left(-1dfrac{1}{3}right).left(-1dfrac{1}{4}right)...left(-1dfrac{1}{299}right)
C -dfrac{7}{4}.left(dfrac{33}{12}+dfrac{3333}{2020}+dfrac{3333}{3030}+dfrac{333333}{424242}right)
Đọc tiếp
Thu gọn các biểu thức sau
A = \(\left(-2\right).\left(-1\dfrac{1}{2}\right).\left(-1\dfrac{1}{3}\right).\left(-1\dfrac{1}{4}\right)...\left(-1\dfrac{1}{214}\right)\)
B = \(\left(-1\dfrac{1}{2}\right).\left(-1\dfrac{1}{3}\right).\left(-1\dfrac{1}{4}\right)...\left(-1\dfrac{1}{299}\right)\)
C = \(-\dfrac{7}{4}.\left(\dfrac{33}{12}+\dfrac{3333}{2020}+\dfrac{3333}{3030}+\dfrac{333333}{424242}\right)\)
a, 1 + dfrac{1}{2}.(1+2)+dfrac{1}{3}.(1+2+3)+...+dfrac{1}{16}.(1+2+3+...+16)b, left[left(dfrac{2}{196}-dfrac{3}{386}right).dfrac{193}{17}+dfrac{33}{34}right]:left[left(dfrac{7}{1931}+dfrac{11}{3862}right).dfrac{1931}{25}+dfrac{9}{2}right]c, dfrac{dfrac{1}{2}-dfrac{1}{7}-dfrac{1}{13}}{dfrac{2}{3}-dfrac{2}{7}-dfrac{2}{13}}xdfrac{dfrac{3}{4}-dfrac{3}{16}-dfrac{3}{64}-dfrac{3}{256}}{1-dfrac{1}{4}-dfrac{1}{16}-dfrac{1}{64}}+dfrac{5}{8}d, dfrac{0,125-dfrac{1}{5}+dfrac{1}{7}}{0,375-dfrac{3}{5}+dfrac{3}...
Đọc tiếp
a, 1 + \(\dfrac{1}{2}\).(1+2)+\(\dfrac{1}{3}\).(1+2+3)+...+\(\dfrac{1}{16}\).(1+2+3+...+16)
b, \(\left[\left(\dfrac{2}{196}-\dfrac{3}{386}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]\):\(\left[\left(\dfrac{7}{1931}+\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
c, \(\dfrac{\dfrac{1}{2}-\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}-\dfrac{2}{7}-\dfrac{2}{13}}\)x\(\dfrac{\dfrac{3}{4}-\dfrac{3}{16}-\dfrac{3}{64}-\dfrac{3}{256}}{1-\dfrac{1}{4}-\dfrac{1}{16}-\dfrac{1}{64}}\)+\(\dfrac{5}{8}\)
d, \(\dfrac{0,125-\dfrac{1}{5}+\dfrac{1}{7}}{0,375-\dfrac{3}{5}+\dfrac{3}{7}}\)+\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}-0,2}{\dfrac{3}{4}+0,5-\dfrac{3}{10}}\)