Đặt \(B=1+2+2^2+2^3+...+2^{2009}\)
\(\Rightarrow2B=2+2^2+2^3+2^4+...+2^{2010}\)
\(\Rightarrow2B-B=\left(2+2^2+2^3+2^4+...+2^{2010}\right)-\left(1+2+2^2+2^3+...+2^{2009}\right)\)
\(\Rightarrow B=2^{2010}-1\)
\(\Rightarrow A=\dfrac{1+2+2^2+2^3+...+2^{2009}}{2^{2010}-1}\)
\(=\dfrac{2^{2010}-1}{2^{2010}-1}\)
\(=1\)
giải các ptr sau
a)\(\dfrac{2-x}{2008}-1=\dfrac{1-x}{2009}-\dfrac{x}{2010}\)
b)\(\dfrac{x}{3}-\dfrac{2x+1}{2}=\dfrac{x}{6}-x\)
Giải phương trình sau:
\(\dfrac{x-1}{2013}+\dfrac{x-2}{2012}+\dfrac{x-3}{2011}=\dfrac{x-4}{2010}+\dfrac{x-5}{2009}+\dfrac{x-6}{2008}\)
Giải phương trình sau:
\(\dfrac{x-1}{2013}+\dfrac{x-2}{2012}+\dfrac{x-3}{2011}=\dfrac{x-4}{2010}+\dfrac{x-5}{2009}+\dfrac{x-6}{2008}\)
Ai giúp mình với,cô cho toàn bài khó.
B1:
a)Tìm x,y biết (x+y)^2=(x-1)(y+1)
b)Tìm x,y,z biết :9x^2+y^2+2z^2-18x+4z-6y +20=0
B2:
Cho x/a+y/b+z/c=1 và-a/x+b/y+c/z=0
C/m x^2/a^2 +y^2/b^2 +z^2/c^2=1
B3:
Tìm x
(2009-x)^2+(2009-x)(x-2010)+(x-2010)^2/(2009-x)^2-(2009-x)(x-2010)+(x-2010)^2=19/49
Giải phương trình:
\(8\left(x+\frac{1}{x}\right)^2+4\left(x^2+\frac{1}{^{x^2}}\right)^2-4\left(x^2+\frac{1}{x^2}\right)\left(x+\frac{1}{x}\right)^2=\left(x+4\right)^2\)
\(\frac{\left(2009-x\right)^2+\left(2009-x\right)\left(x-2010\right)+\left(x-2010\right)^2}{\left(2009-x\right)^2-\left(2009-x\right)\left(x-2010\right)+\left(x-2010\right)^2}=\frac{19}{49}\)
giải phương trình: \(\frac{x+1}{2010}+\frac{x+2}{2009}+\frac{x+3}{2008}+...+\frac{x+2009}{2}+\frac{x+2010}{1}\)\(=\left(-2010\right)\)
Giải Phương trình
\(\left(2x-1\right)^3+\left(x+2\right)^3=\left(3x+1\right)^3\)
\(\frac{x-1988}{15}+\frac{x-1969}{17}+\frac{x-1946}{19}+\frac{x-1919}{21}=10\)
\(\frac{\left(2009-x\right)^2+\left(2009-x\right)\left(x-2010\right)+\left(x-2010\right)^2}{\left(2009-x^2\right)-\left(2009-x\right)\left(x-2010\right)+\left(x-2010\right)^2}=\frac{19}{49}\)
a)3,6-0,5(2x-1)=3x-0,25(3-4x)
b)5x^2-4x-1=0
c)2-x/2008-1=1-x/2009-x/2010
Tính:
A = 12-22+32-42+...+20092-20102+20112
