Cho A=\(\frac{4bc-a^2}{bc+2a^2}\),B=\(\frac{4ca-b^2}{ac+2b^2}\),C=\(\frac{4ab-c^2}{ab+2c^2}\)
Chứng minh : Nếu a+b+c=0 thì A.B.C=1
Cho A=\(\frac{4bc-a^2}{bc+2a^2}\),B=\(\frac{4ca-b^2}{ac+2b^2}\),C=\(\frac{4ab-c^2}{ab+2c^2}\).CMR nếu a+b+c=0 thì A.B.C=1
Cho \(a+b+c=0\), đặt \(A=\frac{4bc-a^2}{bc+2a^2}\);\(B=\frac{4ca-b^2}{ca+2b^2}\);\(C=\frac{4ab-c^2}{ab+2c^2}\).Chứng minh rằng: \(A.B.C=1\)
cho a+b+c=0 .
Chứng minh a, \(\frac{4bc-a^2}{bc+2a^2}.\frac{4ab-c^2}{ab+2c^2}.\frac{4ac-b^2}{ac+2b^2}\)=1
b, \(\frac{4bc-a^2}{bc+2a^2}+\frac{4ab-c^2}{ab+2c^2}+\frac{4ac-b^2}{ac+2b^2}\)=3
a/ \(\frac{4bc-a^2}{bc+2a^2}.\frac{4ab-c^2}{ab+2c^2}.\frac{4ac-b^2}{ac+2b^2}\)
\(=\frac{4bc-\left(b+c\right)^2}{bc+2\left(b+c\right)^2}.\frac{4\left(-b-c\right)b-c^2}{\left(-b-c\right)b+2c^2}.\frac{4\left(-b-c\right)c-b^2}{\left(-b-c\right)c+2b^2}\)
\(=\frac{-\left(b-c\right)^2}{\left(c+2b\right)\left(b+2c\right)}.\frac{-\left(c+2b\right)^2}{-\left(b-c\right)\left(b+2c\right)}.\frac{-\left(b+2c\right)^2}{\left(b-c\right)\left(c+2b\right)}=1\)
Cho \(a+b+c=0\) , Đặt \(A=\frac{4bc-a^2}{bc+2a^2},B=\frac{4ca-b^2}{ca+2b^2},C=\frac{4ab-c^2}{ab+2c^2}\)
Chứng minh rằng : \(A.B.C=1\)
Giúp mk vs thanks mn
Cho phân thức A=\(\frac{4bc-a^2}{bc+2a^2}\);B=\(\frac{4ca-b^2}{ca+2b^2}\);C=\(\frac{4ab-c^2}{ab+2c^2}\)
Cmr nếu a+b+c=0 a khác b khác c thì A.B.C=1
Bạn nào giải nhanh đúng mình tick cho nha ^ ^.
\(A=\dfrac{4bc-a^2}{bc+2a^2}\\ B=\dfrac{4ca-b^2}{ca+2b^2}\\ C=\dfrac{4ab-c^2}{ab+2c^2}\\ \)
CMR: nếu a+b+c=0 thì A.B.C=1
cho A=(4bc-a2)/(bc+2a2); B=(4ca-b2)/(ca+2a2); C=(4ab-c2)/(ab+2c2)
Chứng minh rằng nếu a+b+c=0 thì a.b.c=1
Cho a, b, c > 0 thỏa mãn a.b.c=1. Chứng minh rằng: \(\frac{bc}{a^2b+a^2c}+\frac{ac}{b^2a+b^2c}+\frac{ab}{c^2a+c^2b}\ge\frac{3}{2}\)
\(VT=\frac{b^2c^2}{b+c}+\frac{a^2c^2}{a+c}+\frac{a^2b^2}{a+b}\ge\frac{\left(ab+bc+ca\right)^2}{2\left(a+b+c\right)}\ge\frac{3abc\left(a+b+c\right)}{2\left(a+b+c\right)}=\frac{3}{2}\)
Dấu "=" xảy ra khi \(a=b=c=1\)