Theo t/c dãy tỉ số bằng nhau ta có :
\(\dfrac{a}{b}=\dfrac{c}{d}=\dfrac{a+c}{b+d}\)
Vậy \(\dfrac{a}{b}=\dfrac{c+c}{b+d}\left(đpcm\right)\)
cho \(\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}\)
CMR : \(\left(\dfrac{a}{b}+\dfrac{b}{c}+\dfrac{c}{d}\right)^2\) = \(\dfrac{a}{d}\)
Chứng minh rằng từ tỉ lệ thức \(\dfrac{a}{b}=\dfrac{c}{d};\left(a-b\ne0;c-d\ne0\right)\) ta có thể suy ra tỉ lệ thức \(\dfrac{a+b}{c-b}=\dfrac{c+d}{c-d}\) ?
cho \(\dfrac{a}{b}=\dfrac{c}{d}\)CMR
\(\left(\dfrac{a-b}{c-d}\right)^2=\dfrac{ab}{cd}\)
cho a+b+c+d khác 0 vàti\(\dfrac{b+c+d-a}{a}=\dfrac{c+d+a-b}{b}=\dfrac{d+a+b-c}{c}=\dfrac{a+b+c-d}{d}P=\left(1+\dfrac{b}{a}\right)\left(1+\dfrac{c}{b}\right)\left(1+\dfrac{c}{d}\right)\left(1+\dfrac{a}{d}\right)\)tính P
giúp mk với ạ , xin cảm ơn
Cho \(\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}\) CMR :\(\left(\dfrac{a+b+c}{b+c+d}\right)^3=\dfrac{a}{d}\)
Cho tỉ le thức\(\dfrac{a}{b}=\dfrac{c}{d}\left(b,d\ne0\right)\).Chung minh rang \(\dfrac{ac}{bd}=\dfrac{a^2+c^2}{b^2+d^2}\)
\(cho\)cho:\(\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}.\) cmr: \(\left(\dfrac{a+b+c}{b+c+d}\right)^3=\dfrac{a}{d}\)
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 \(\dfrac{b+c-5}{a}=\dfrac{a+c+2}{b}=\dfrac{a+b+3}{c}=\dfrac{1}{a+b+c}\left(a,b,c\ne0,a+b+c\ne0\right)\)
Tính \(\left(a-3b\right)\left(b-c\right)\left(3c-a\right)\)
Ai giúp mik đi, mik cho 5 coin
