Tính: (1-1/1+2)x(1-1/1+2+3)x(1-1/1+2+3+4)x...x(1-1/1+2+3+4+...+99+100)
Những câu hỏi liên quan
(2+4+6+...+100) - (1+3+5+...+99) = ?
1 x 2 + 2 x 3 + 3 x 4 + ... + 99 x 100 = ?
3 x 4 + 4 x 5 + 5 x 6 + ... + 149 x 150 = ?
1 + (1 + 2) + ( 1 + 2 + 3) + (1 + 2 + 3 + 4) + ....... + (1 + 2 + 3 + ... + 99)
----------------------------------------------------------------------------------------------------------- ( gạch ngang phân số )
1 x 99 + 2.98 + 3.97 + ...... + 99 x 1
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1. Tính nhanh:
M = 1 x 1/2 + 1/2 x 1/3 + 1/3 x 1/4 +...+ 1/99 x 1/100
M = \(\dfrac{1}{1x2}+\dfrac{1}{2x3}+\dfrac{1}{3x4}+...+\dfrac{1}{99x100}\)
M = \(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}\)
M = \(1-\dfrac{1}{100}\)
M = \(\dfrac{99}{100}\)
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1. Tính nhanh:
M = 1 x 1/2 + 1/2 x 1/3 + 1/3 x 1/4 +...+ 1/99 x 1/100
cíu :))
\(M=1\times\dfrac{1}{2}+\dfrac{1}{2}\times\dfrac{1}{3}+\dfrac{1}{3}\times\dfrac{1}{4}+...+\dfrac{1}{99}\times\dfrac{1}{100}\)
\(M=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}\)
\(M=1-\dfrac{1}{100}\)
\(M=\dfrac{99}{100}\)
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Tính:
P = (1 - 2 / 2 x 3) (1 - 2 / 3 x 4) (1 - 2 / 4 x 5) x . . . x (1 - 2 / 99 x 100)
Ta có :
\(P=\left(1-\frac{2}{2.3}\right)\left(1-\frac{2}{3.4}\right)\left(1-\frac{2}{4.5}\right)...\left(1-\frac{2}{99.100}\right)\)
\(P=\frac{4}{2.3}.\frac{10}{3.4}.\frac{18}{4.5}....\frac{9898}{99.100}\)
\(P=\frac{1.4}{2.3}.\frac{2.5}{3.4}.\frac{3.6}{4.5}....\frac{98.101}{99.100}\)
\(P=\frac{1.2.3...98}{2.3.4....99}.\frac{4.5.6....101}{3.4.5...100}\)
\(P=\frac{1}{99}.\frac{101}{3}=\frac{101}{297}\)
Ủng hộ mk nha !!! ^_^
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\(P=\left(1-\frac{2}{2.3}\right)\left(1-\frac{2}{3.4}\right)\left(1-\frac{2}{4.5}\right)...\left(1-\frac{2}{99.100}\right)\)
\(P=\frac{4}{2.3}.\frac{10}{3.4}.\frac{18}{4.5}...\frac{9898}{99.100}\)
\(P=\frac{1.4}{2.3}.\frac{2.5}{3.4}.\frac{3.6}{4.5}...\frac{98.101}{99.100}\)
\(P=\frac{1.2.3...98}{2.3.4...99}.\frac{4.5.6...101}{3.4.5...100}\)
\(P=\frac{1}{99}.\frac{101}{3}=\frac{101}{297}\)
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1 tính tổng các số nguyên x biết
1/ -20<x<21
2/ -18 ≤ x ≤17
3/ -27 < x ≤ 27
4/ | x | ≤ 3
5/ | -x | <5
2 tính tổng
1/ 1+(-2)+3+(-4)+...+19+(-20)
2/ 1-2+3-4+...+99-100
3/ 2-4+6-8+...+48-50
4/ -1+3-5+7-....+97-99
5/ 1+2-3-4+....+97+98-99-100
A=(1+1/2).(1+1/3).(1+1/4)...(1×1/2009)
B=(1-1/2).(1-1/3)...(1-1/100)
B= 1/2.2/3.3/4...99/100
X+1/99+x+2/98+x+3/97+x+4/96
\(A=\frac{3}{2}.\frac{4}{3}.\frac{5}{4}........\frac{2010}{2009}=\frac{3.4.5...2010}{2.3.4....2009}=\frac{2010}{2}=1005\)
\(B=\frac{1.2.3......99}{1.2.3.4.....100}=\frac{1}{100}\)
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1/1 x 1/2 + 1/2 x 1/3 + 1/3 + 1/4 + .......... + 1/9 x 1/10
2/1 x 2 + 2/2 x 3 + 2/3 x4 + .............. + 2/98 x 99 + 2/99 x 100
= 1/1x2 + 1/2x3 + 1/3x4 ...... +1/9x10
= 1-1/2+1/2-1/3+1/3-1/4+........+1/9-1/10
=1-1/10=9/10
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đặt A=1/1 x 1/2 + 1/2 x 1/3 + 1/3 + 1/4 + .......... + 1/9 x 1/10
\(A=\frac{1}{1}\cdot\frac{1}{2}+\frac{1}{2}\cdot\frac{1}{3}+...+\frac{1}{9}\cdot\frac{1}{10}\)
\(=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{9.10}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{9}-\frac{1}{10}\)
\(=1-\frac{1}{10}\)
\(=\frac{9}{10}\)
đặt B=2/1 x 2 + 2/2 x 3 + 2/3 x4 + .............. + 2/98 x 99 + 2/99 x 100
\(B=2\left(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{99.100}\right)\)
\(=2\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\right)\)
\(=2\left(1-\frac{1}{100}\right)\)
\(=2\times\frac{99}{100}\)
\(=\frac{99}{50}\)
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Tính x - y biết:
x = 1 . 2 + 2 . 3 + 3 . 4 + ... + 99 . 100
y = 1 . 1 + 2 . 2 + 3 . 3+ ... + 99 . 99
Ta có : x = 1.2 + 2.3 + 3.4 + ... + 99.100
= 1.(1 + 1) + 2.(2 + 1) + ... + 99.(99 + 1)
= 1.1 + 1 + 2.2 + 2 + ... + 99.99 + 99
= (1.1 + 2.2 + 3.3 + ... + 99.99) + (1 + 2 + 3 + ... + 99)
= y + 99.(99 + 1) : 2
= y + 99.50
= y + 4950
=> x = y + 4950
=> x - y = 4950
Vậy x - y = 4950
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bn nhân 3 vào x và y rồi l x - y là s
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1, Tính \(\frac{1}{2}-\left(\frac{1}{3}+\frac{2}{3}\right)+\left(\frac{1}{4}+\frac{2}{4}+\frac{3}{4}\right)-\left(\frac{1}{5}+\frac{2}{5}+\frac{3}{5}+\frac{4}{5}\right)+...+\left(\frac{1}{100}+\frac{2}{100}+\frac{3}{100}+...+\frac{99}{100}\right)\)2,Tính \(\left(1-\frac{1}{2^2}\right)x\left(1-\frac{1}{3^2}\right)x\left(1-\frac{1}{4^2}\right)x...x\left(1-\frac{1}{n^2}\right)\)
