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\(\left(a-2009\right)^2+\left(b+2010\right)^2=0\)
\(\Rightarrow\hept{\begin{cases}a-2009=0\\b+2010=0\end{cases}\Rightarrow\hept{\begin{cases}a=2009\\b=-2010\end{cases}}}\)
Vậy : ...................
Vì (a - 2009) và ( b + 2010) có số mũ chẵn
Nên : nếu giá trị của ( a - 2009) và ( b + 2010) bé hơn hoặc lớn hơn 0 thì tổng 2 số không thể bằng 0
=> \(\hept{\begin{cases}a-2009=0\\b+2010=0\end{cases}\Rightarrow\hept{\begin{cases}a=2009\\b=-2010\end{cases}}}\)
Ta thấy :
\(\left\{{}\begin{matrix}\left(a-2009\right)^2\ge0\\\left(b+2010\right)^2\ge0\end{matrix}\right.\)
Mà \(\left(a-2009\right)^2+\left(b+2010\right)^2=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(a-2009\right)^2=0\\\left(b+2010\right)^2=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}a-2009=0\\b+2010=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}a=2009\\b=-2010\end{matrix}\right.\)
Vậy ............
\(\left(a-2009\right)^2+\left(b+2010\right)^2=0\)
\(\Rightarrow\left\{{}\begin{matrix}\left(a-2009\right)^2=0\\(b+2010)^2=0\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}a-2009=0\\b+2010=0\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}a=2009\\b=-2010\end{matrix}\right.\)
vậy \(a=2009\)
\(b=-2010\)
chúc bạn học tốt
\(A>B\),có lẽ là bởi vì \(A\)có mũ 2010 ;còn \(B\)thì lại có mũ 2009.
a: Đặt a/b=c/d=k
=>a=bk; c=dk
\(\left(\dfrac{a+b}{c+d}\right)^2=\left(\dfrac{bk+b}{dk+d}\right)^2=\dfrac{b^2}{d^2}\)
\(\dfrac{a^2+b^2}{c^2+d^2}=\dfrac{b^2k^2+b^2}{d^2k^2+d^2}=\dfrac{b^2}{d^2}\)
Do đó: \(\left(\dfrac{a+b}{c+d}\right)^2=\dfrac{a^2+b^2}{c^2+d^2}\)
b: \(\dfrac{ab}{cd}=\dfrac{bk\cdot b}{dk\cdot d}=\dfrac{b^2}{d^2}\)
\(\left(\dfrac{a-b}{c-d}\right)^2=\left(\dfrac{bk-b}{dk-d}\right)^2=\dfrac{b^2}{d^2}\)
Do đó: \(\dfrac{ab}{cd}=\left(\dfrac{a-b}{c-d}\right)^2\)
Đặt \(\frac{a}{2008}=\frac{b}{2009}=\frac{c}{2010}=k\)
suy ra: \(a=2008k;\) \(b=2009k;\)\(c=2010k\)
Khi đó ta có: \(4\left(a-b\right)\left(b-c\right)\)
\(=4\left(2008k-2009k\right)\left(2009k-2010k\right)\)
\(=4k^2\)
\(\left(c-a\right)^2=\left(2010k-2008k\right)^2=4k^2\)
suy ra: \(4\left(a-b\right)\left(b-c\right)=\left(c-a\right)^2\) (đpcm)
p/s: tham khảo,
Ta có: \(\frac{a}{2009}=\frac{b}{2010}=\frac{c}{2011}.\)
Áp dụng tính chất dãy tỉ số bằng nhau ta được:
\(\frac{a}{2009}=\frac{b}{2010}=\frac{c}{2011}=\frac{a-b}{2009-2010}=\frac{b-c}{2010-2011}=\frac{c-a}{2011-2009}.\)
\(\Rightarrow\frac{a-b}{-1}=\frac{b-c}{-1}=\frac{c-a}{2}\)
\(\Rightarrow\frac{a-b}{-1}.\frac{b-c}{-1}=\left(\frac{c-a}{2}\right)^2\)
\(\Rightarrow\frac{\left(a-b\right).\left(b-c\right)}{1}=\frac{\left(c-a\right)^2}{2^2}\)
\(\Rightarrow\frac{\left(a-b\right).\left(b-c\right)}{1}=\frac{\left(c-a\right)^2}{4}.\)
\(\Rightarrow4.\left(a-b\right).\left(b-c\right)=\left(c-a\right)^2.1\)
\(\Rightarrow4.\left(a-b\right).\left(b-c\right)=\left(c-a\right)^2\)
\(\Rightarrow4.\left(a-b\right).\left(b-c\right)-\left(c-a\right)^2=0.\)
Hay \(M=0.\)
Vậy \(M=0.\)
Chúc bạn học tốt!
Ta có \(\dfrac{a}{2009}\)=\(\dfrac{b}{2010}\)=\(\dfrac{c}{2011}\)
Áp dụng tính chất của dãy tỉ số bằng nhau ta có:
\(\dfrac{a}{2009}=\dfrac{b}{2010}=\dfrac{c}{2011}=\dfrac{c-a}{2011-2009}=\dfrac{c-a}{2}\left(1\right)\)
\(\dfrac{a}{2009}=\dfrac{b}{2010}=\dfrac{c}{2011}=\dfrac{a-b}{2009-2010}=\dfrac{a-b}{-1}\)(2)\(\dfrac{a}{2009}=\dfrac{b}{2010}=\dfrac{c}{2011}=\dfrac{b-c}{2010-2011}=\dfrac{b-c}{-1}\left(3\right)\)
Từ (1),(2),(3) \(_{\Rightarrow}\)\(\dfrac{c-a}{2}=\dfrac{a-b}{-1}=\dfrac{b-c}{-1}\Rightarrow\dfrac{\left(a-c\right)^{ }2}{2^{ }2}=\dfrac{\left(a-b\right)}{-1}\times\dfrac{\left(b-c\right)}{-1}\)
\(\Rightarrow\dfrac{\left(a-c\right)^2}{4}=\dfrac{\left(a-b\right)\times\left(b-c\right)}{1}\Rightarrow4\left(a-b\right).\left(b-c\right)=\left(a-c\right)^2\)
\(\Rightarrow M=4\left(a-b\right).\left(a-c\right)-\left(c-a\right)^2=0\)
Vậy M = 0
đặt \(\dfrac{a}{2009}=\dfrac{b}{2010}=\dfrac{c}{2011}=k\) ta có:
\(\Rightarrow a=2009k\left(1\right)\\ \Rightarrow b=2010k\left(2\right)\\ \Rightarrow c=2011k\left(3\right)\)
thay 1;2;3 vào M ta có:
\(M=4\left(2009k-2010k\right)\left(2010k-2011k\right)-\left(2011k-2009k\right)^2\\ \Rightarrow M=4.\left(-k\right)\left(-k\right)-\left(2k\right)^2\\ \Rightarrow M=4k^2-\left(2k\right)^2\\ \Rightarrow M=\left(2k\right)^2-\left(2k\right)^2\\ \Rightarrow M=0\)Vậy M = 0
a) \(\left(a-2009\right)^2+\left(b+2010\right)^2=0\)
vì \(\left(a-2009\right)^2\ge0\) \(\left(b+2010\right)^2\ge0\)
suy ra \(a-2009=0\Rightarrow a=2009\)
\(b+2010=0\Rightarrow b=-2010\)
b) \(\left|a-2010\right|=2009\)
* Nếu \(a-2010\ge0\Rightarrow a>2010\)
\(a-2010=2009\)
\(a=4019\)(TMĐK)
* Nếu \(a-2010< 0\Rightarrow a< 2010\)
\(-\left(a-2010\right)=2009\)
\(a=1\)(TMĐK)
Vậy \(a=4019\) hoặc \(a=1\)