đề bài chưa đầy đủ mk lam ko dc
suy ra a.c=b^2 . Ta co : a/b=b/c suy ra a^2/b^2=b^2/c^2=(a^2+b^2)/(b^2+c^2)=(a^2 +a.c)/(a.c+c^2)=a.(a+c)/c(a+c)=a/c
cho \(\dfrac{a}{b}=\dfrac{c}{d}\)
CMR : \(\dfrac{a^2+b^2}{b^2+c^2}\) = \(\dfrac{a}{c}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\)
CMR: \(\dfrac{a.c}{b.d}\) = \(\dfrac{a^2+c^2}{b^2+d^2}\)
Cho \(\dfrac{a}{c}=\dfrac{c}{b}.CMR:\)
a, \(\dfrac{a^2+c^2}{b^2+c^2}=\dfrac{a}{b}\)
b, \(\dfrac{b^2-a^2}{a^2+c^2}=\dfrac{b-a}{a}\)
cho \(\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}\)
CMR : \(\left(\dfrac{a}{b}+\dfrac{b}{c}+\dfrac{c}{d}\right)^2\) = \(\dfrac{a}{d}\)
Cho tỉ lệ thức \(\dfrac{a}{b}=\dfrac{c}{d}\). CMR : \(\dfrac{ab}{cd}=\dfrac{a^2-b^2}{c^2-d^2}\) và \(\left(\dfrac{a+b}{c+d}\right)^2=\dfrac{a^2+b^2}{c^2+d^2}\)
cho \(\dfrac{a}{b}=\dfrac{c}{d}\)CMR
\(\left(\dfrac{a-b}{c-d}\right)^2=\dfrac{ab}{cd}\)
Cho tỉ lệ thức \(\dfrac{a}{b}=\dfrac{c}{d}\). CMR: \(\dfrac{a^2-b^2}{ab}=\dfrac{c^2-d^2}{cd}\)
Cho a; b; c; x; y; z và \(x^2-yz\ne0;y^2-zx\ne0;z^2-xy\ne0\) thỏa mãn \(\dfrac{x^2-yz}{a}=\dfrac{y^2-xz}{b}=\dfrac{z^2-xy}{c}\). CMR \(\dfrac{a^2-bc}{x}=\dfrac{b^2-ca}{y}=\dfrac{c^2-ab}{z}\)
cho \(a^2=bc\). cmr: \(\dfrac{c}{d}=\dfrac{a^2+c^2}{b^2+a^2}\)
