1-x^3-x^5-x^7-......-x^2015. Mà x = -1
Những câu hỏi liên quan
1/2015 x 2/2015 x 3/2015 x 4/2015 x 5/2015 x .... x 10/2015
Trả lời nời tớ nhé. Tớ sẽ tick cho. Nhưng mà phải đúng đấy
Tính:
a) 2^5 x 13^12 x 7^8 : 27 x 13^10 x 7^9
b) 2^n x 11 x 3 : 6^n x 3
c) 5^5 x 7 x 9^5 : 15^10
d) 7 x 8^10 x 27^9 - 8 x 9^13 x 2^27 : 7 x 6^26 x 2^2 - 2^4 x 8^3 x 27^9
e) 2^2^1^2015
f) 2015^0^2015^0^2015
72-8/3 bằng bao nhiêu số tự nhiên
Tính:
a) 2^5 x 13^12 x 7^8 : 2^7 x 13^10 x 7^9
b) 2^n x 11 x 3 : 6^n x 3
c) 5^5 x 7 x 9^5 : 15^10
d) 7 x 8^10 x 27^9 - 8 x 9^13 x 2^27 : 7 x 6^26 x 2^2 - 2^4 x 8^3 x 27^9
e) 2^2^1^2015
f) 2015^0^2015^0^2015
1. tìm x biết (3/1*3 + 3/3*5 + 3/5*7 +......+ 3/97*99) - x : 3/2 = 7/3
2. tìm số tự nhiên x,y biết (x-y)^2015 = 5^2015 và phân số x/y rút gọn được thành 4/3
1.
\(\left(\frac{3}{1\times3}+\frac{3}{3\times5}+\frac{3}{5\times7}+...+\frac{3}{97\times99}\right)-x:\frac{3}{2}=\frac{7}{3}\\
\left(\frac{2}{1\times3}+\frac{2}{3\times5}+\frac{2}{5\times7}+...+\frac{2}{97\times99}\right):\frac{3}{2}-x:\frac{3}{2}=\frac{7}{3}\\\left[\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{99}\right)-x\right]:\frac{3}{2}=\frac{7}{3}\\
\left(1-\frac{1}{99}\right)-x=\frac{7}{3}\times\frac{3}{2}\\
\frac{98}{99}-x=\frac{7}{2}\\
x=\frac{98}{99}-\frac{7}{2}=\frac{-497}{198}\)
2.\(\frac{x}{y}=\frac{4}{3}\Rightarrow\hept{\begin{cases}x=4a\\y=3a\\x-y=4a-3a=a\end{cases}}\\ \left(x-y\right)^{2015}=5^{2015}\Rightarrow x-y=5\\ \Rightarrow a=5\Rightarrow\hept{\begin{cases}x=4\times5=20\\y=3\times5=15\end{cases}}\)
1.
(31×3+33×5+35×7+...+397×99)−x:32=73(21×3+23×5+25×7+...+297×99):32−x:32=73[(1−13+13−15+15−17+...+197−199)−x]:32=73(1−199)−x=73×32
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a,
x-2/3-2/15-2/35-2/63=1/9
b
(x+1
3)+(x+1/9)+(x+1/27)+(x+1/81)=56/81
c,
(1/3*5+1/5*7+1/7*9+.....+1/19*21)*x=9/7
d,3+5+7+...+2015/2+4+6+...+2016+x=1
e,2/6+2/12+2/20+...+2/x*(x+1)=2013/2015
a) 2x-1/11+2x-2/12+2x-3/13=2x+5/5+2x+6/4+2x+7/3
b) x-1/2016+x-2/2015+x-3/2014+x-4/2013+x-5/2012 -5=0
c) x+2017/2+x+2015/3+x+2013/4+x+2011/5+8=0
(x + 1) + (x + 3) + (x + 5) + (x + 7) + . . . + (x + 2015) = 1023120
x =
Số dấu ngoặc = (2015 - 1):2 +1 = 1008
=> 1008x +(2015+ 1).1008:2 = 1023120
=> 1008x + 1008.1008 = 1008.1015
=> x +1008 = 1015
x = 7
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x-1 / 2015 + x-3 / 2013 = x-5 / 2011 + x-7 / 2009
\(\frac{x-1}{2015}+\frac{x-3}{2013}=\frac{x-5}{2011}+\frac{x-7}{2009}\)
=> \(\frac{x-1}{2015}-1+\frac{x-3}{2013}-1=\frac{x-5}{2011}-1+\frac{x-7}{2009}-1\)
=> \(\frac{x-2016}{2015}+\frac{x-2016}{2013}=\frac{x-2016}{2011}+\frac{x-2016}{2009}\)
=> \(\frac{x-2016}{2009}+\frac{x-2016}{2011}-\frac{x-2016}{2013}-\frac{x-2016}{2015}=0\)
=> \(\left(x-2016\right).\left(\frac{1}{2009}+\frac{1}{2011}-\frac{1}{2013}-\frac{1}{2015}\right)\)
Vì \(\frac{1}{2009}>\frac{1}{2013};\frac{1}{2011}>\frac{1}{2015}\)
=> \(\frac{1}{2009}+\frac{1}{2011}-\frac{1}{2013}-\frac{1}{2015}\ne0\)
=> \(x-2016=0\)
=> \(x=2016\)
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Bài 5: Tính nhanh
A = 1/1 x3 + 1/ 3 x 5 + 1/ 5 x 7 + ................. + 1/ 2013 x 2015
A x 2 = 2/1 x3 + 2/ 3 x 5 + 2/ 5 x 7 + ................. + 2/ 2013 x 2015
= 1/1 – 1/3 + 1/3 – 1/5 + 1/5 – 1/7 + .................. + 1/2013 – 1/2015
= 1 – 1/2015 = 2014/2015
Vậy A = 2014/2015 : 2 = 2014/4030.
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