cho \(\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}\) a,b,c,d khác 0
CMR: \(\frac{a}{b}=\frac{c}{d}\) hoặc \(\frac{a}{b}=\frac{d}{c}\)
\(\frac{a^2+b^2}{c^2+d^2}=\frac{a.b}{c.d}.Cmr:\frac{a}{b}=\frac{c}{d}\)
Cho \(\frac{a}{b}=\frac{c}{d}\)
cmr : \(\left(\frac{a+b}{c+d}\right)^2=\frac{a^2+b^2}{c^2+d^2}\)
Cho \(\frac{a}{b}=\frac{c}{d}\)
CMR : \(\frac{ac}{bd}=\frac{a^2+c^2}{b^2+d^2}\)
Cho \(\frac{a}{b}=\frac{c}{d}\)
cmr : \(\left(\frac{a+b}{c+d}\right)^2=\frac{a^2+b^2}{c^2+d^2}\)
Bài 1: CMR: \(\frac{11}{15}< \frac{1}{21}+\frac{1}{22}+\frac{1}{23}+...+\frac{1}{59}+\frac{1}{60}< \frac{3}{2}\)\(.\)
Bài 2: Cho các số nguyên dương a,b,c,d.
CTR: \(1< \frac{a}{a+b+c}+\frac{b}{b+c+d}+\frac{c}{c+d+a}+\frac{d}{d+a+b}< 2\)
Ai nhanh nhất mình \(tick\)cho!
2) cho\(\frac{a}{b}=\frac{c}{d}\)
CMR: \(\frac{a}{a+c}=\frac{b}{b+c}\)với a+c khác 0, b+d khác 0
2)Cho \(\frac{a}{b}=\frac{c}{d}\)
CMR : \(\frac{a}{a+c}=\frac{b}{b+d}\)với a + c khác 0 , b + d khác 0
cho a,b,c,d thoả mãn \(\frac{a}{b+c+d}+\frac{b}{c+d+a}+\frac{c}{d+a+b}+\frac{d}{a+b+c}=1\)
Tính \(\frac{a^2}{b+c+d}+\frac{b^2}{c+d+a}+\frac{c^2}{d+a+b}+\frac{d^2}{a+b+c}\)
