(a^2+b^2)/(c^2+d^2)=a^2/c^2=b^2/d^2(theo t/c dãy tỉ số bằng nhau)
a^2/c^2=ab/cd<=>a/c=b/d<=>a/b=c/d(đpcm)
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Cho : \(\frac{a}{b}=\frac{c}{d}CMR:\)\(\frac{ab}{cd}=\frac{a^2-b^2}{c^2-d^2}v\text{à}\left(\frac{a+b}{c+d}\right)^2=\frac{a^2+b^2}{c^2+d^2}\)
Cho \(\frac{a}{b}=\frac{c}{d}\). CMR:
a) \(\frac{a^2-b^2}{c^2-d^2}=\frac{ab}{cd}\)
b) \(\frac{\left(a-b\right)^2}{\left(c-d\right)^2}=\frac{ab}{cd}\)
Cho tỉ lệ thức \(\frac{a}{b}=\frac{c}{d}.CMR:\frac{ab}{cd}=\frac{a^2-b^2}{c^2-d^2}\)
cho tỉ lệ thức : \(\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}cmr\frac{a}{b}=\frac{c}{d}\)
Cho\(\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}\)
CMR:\(\frac{a}{b}=\frac{c}{d}\)hoặc \(\frac{a}{b}=\frac{d}{c}\)
CMR nếu \(\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}\)(a,b,c,d khác 0). CMR \(\frac{a}{b}=\frac{c}{d}\)hoặc \(\frac{a}{b}=\frac{d}{c}\)
Cho \(\frac{a}{b}=\frac{c}{d}\)CMR \(\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}\)
Cho \(\frac{a}{b}=\frac{c}{d}\), CMR:
a) \(\frac{a^2-b^2}{c^2-d^2}=\frac{ab}{cd}\)
b)\(\frac{\left(a-b\right)^2}{\left(c-d\right)^2}=\frac{ab}{cd}\)
Cho tỉ lệ thức \(\frac{a}{b}=\frac{c}{d}\)CMR
\(\frac{ab}{cd}=\frac{a^2-b^2}{c^2-d^2}\)và \(\left(\frac{a+b}{c+d}\right)^2=\frac{a^2+b^2}{c^2+d^2}\)