Ta có :
\(\frac{a+b-b-c}{2018-2019}=\frac{a-c}{-1}\)
\(\frac{b+c-c-a}{2019-2020}=\frac{b-a}{-1}\)
\(\frac{b-c}{2018-2020}=\frac{b-c}{-2}\)
Đặt \(\frac{a-c}{-1}=\frac{b-a}{-1}=\frac{b-c}{-2}=k\left(k\ne0\right)\)
\(\Rightarrow\hept{\begin{cases}\frac{a-c}{-1}=k\\\frac{b-a}{-1}=k\\\frac{b-c}{-2}=k\end{cases}\Rightarrow\hept{\begin{cases}a-c=-k\\b-a=-k\\b-c=k.\left(-2\right)\end{cases}}}\)
\(\Rightarrowđpcm\)
\(Cho\) \(\frac{a}{2018}=\frac{b}{2019}=\frac{c}{2020}\)CMR
\(4\left(a-b\right)\left(b-c\right)=\left(a-c\right)^2\)
Cho a.b.c thỏa mãn \(\frac{a}{2019}=\frac{b}{2019}=\frac{c}{2020}.\)CMR
\(4\left(a-b\right)\left(b-c\right)=\left(a-c\right)^2\)
Cho a, b, c thỏa mãn \(\frac{a}{2017}=\frac{b}{2018}=\frac{c}{2019}\). Chứng minh \(4\left(a-b\right)\left(c-d\right)=\left(c-a\right)^2\)
cho 3 số đôi 1 khác nhau .CMR:
\(\frac{b-c}{\left(a-b\right)\left(a-c\right)}+\frac{c-a}{\left(b-c\right)\left(b-a\right)}+\frac{a-b}{\left(c-a\right)\left(c-b\right)}=\frac{2}{a-b}+\frac{2}{b-c}+\frac{2}{c-a}\)
Cho 3 số a,b,c đôi một phân biệt. CMR:
\(\frac{b-c}{\left(a-b\right)\left(a-c\right)}+\frac{c-a}{\left(b-c\right)\left(b-a\right)}+\frac{a-b}{\left(c-a\right)\left(c-b\right)}=2\left(\frac{1}{a-b}+\frac{1}{b-c}+\frac{1}{c-a}\right)\\ \)
CMR
\(\frac{1}{2}\left[\frac{b-c}{\left(a-b\right)\left(a-c\right)}+\frac{c-a}{\left(b-c\right)\left(b-a\right)}+\frac{a-b}{\left(c-a\right)\left(c-b\right)}\right]=\frac{1}{a-b}+\frac{1}{b-c}+\frac{1}{c-a}\)
Cho 3 số a,b,c đôi một khác nhau. Cmr:
\(\frac{b-c}{\left(a-b\right)\left(a-c\right)}+\frac{c-a}{\left(b-c\right)\left(b-a\right)}+\frac{a-b}{\left(c-a\right)\left(c-b\right)}\)= \(\frac{2}{a-b}+\frac{2}{b-c}+\frac{2}{c-a}\)
Cho 3 số thực a,b,c thỏa: \(\frac{a}{2016}=\frac{b}{2017}=\frac{c}{2018}\)
CMR: \(4\left(a-b\right)\left(b-c\right)=\left(c-a\right)^2.\)
__Tài liệu chia sẻ vs các bạn, mình đã làm được__
CMR : Nếu a,b,c khác nhau thì :
\(\frac{b-c}{\left(a-b\right)\left(a-c\right)}+\frac{c-a}{\left(b-c\right)\left(b-a\right)}+\frac{a-b}{\left(c-a\right)\left(c-b\right)}=\frac{2}{a-b}+\frac{2}{b-c}+\frac{2}{c-a}\)
