1) Cho \(\frac{a}{b}=\frac{c}{d}\). Chứng minh: \(\frac{a}{3a+b}=\frac{c}{3c+d}\)
2) Cho\(\frac{a}{b}=\frac{c}{d}\). Chứng minh:
a) \(\frac{a^2-d^2}{c^2-d2}=\frac{ab}{cd}\)
b) \(\frac{\left(a-b\right)^2}{\left(c-d\right)^2}=\frac{ab}{cd}\)
Bài 1\(Cho:\frac{a}{b}=\frac{c}{d}chứngminh:\frac{ab}{Cd}=\frac{a^2-b^2}{c^{2-d^2}}Và:\left(\frac{a+b}{c+d}\right)^2=\frac{a^2+b^2}{c^2+d^2}\)
bÀi 2:\(biết:\frac{a^2+b^2}{c^2+d^2}=\frac{ab}{cd}với:a,b,e,dkhác0.chứngminh:\frac{a}{b}=\frac{c}{d}HOẶC:\frac{a}{b}=-\frac{d}{e}\)
Cho tỉ lệ thúc a/b=c/d .C/minh rang ta có các tlt sau
a)\(\frac{3a+5b}{3a-5b}\)=\(\frac{3c+5d}{3c-5d}\)
b)\(\left(\frac{a+b}{c+d}\right)\) =\(\frac{a^2+b^2}{c^2+d^2}\)
c)\(\frac{a-b}{a+b}\)=\(\frac{c-d}{c+d}\)
d)\(\frac{ab}{cd}\)=\(\left(\frac{a-b}{c-d}\right)^2\)
Cho \(\frac{a}{b}=\frac{c}{d}\).CMR :
a/ \(\frac{a+c}{b+d}=\frac{a-c}{b-d}\)
b/\(\frac{2a+3c}{2d+3d}=\frac{2a-3c}{2b-3d}\)
c/\(\frac{a^2+c^2}{b^2+d^2}=\frac{ac^2}{bd}\)
Cho \(\frac{a}{b}=\frac{c}{d}\).Chứng minh rằng :
a ) \(\frac{a+c}{c}=\frac{b+d}{d}\)
b ) \(\frac{3a+5b}{3a-5b}=\frac{3c+5d}{3c-5d}\)
c ) \(\frac{a^2+c^2}{b^2+d^2}=\frac{ab}{bd}\)
Lưu ý : spam + tl linh tinh,cop bài vớ vẩn = báo cáo
Cho \(\frac{a}{b}=\frac{c}{d}\left(a-b\ne0;c-d\ne0\right)\)
Chứng minh : a) \(\frac{a}{3a+b}=\frac{c}{3c+d}\)
b) \(\frac{a^2-b^2}{c^2-d^2}=\frac{ab}{cd}\)
Cho dãy tỉ số bằng nhau \(\frac{3a+b+c+d}{a}=\frac{a+3b+c+d}{b}=\frac{a+b+3c+d}{c}=\frac{a+b+c+3d}{d}\)
Tính Q=\(\left(\frac{a+b}{c+d}\right)^2+\left(\frac{b+c}{a+d}\right)^2+\left(\frac{c+d}{a+b}\right)^2+\left(\frac{a+d}{b+c}\right)^2\)
Cho tỉ lệ thức \(\frac{a}{b}=\frac{c}{d}\)
a,\(\frac{a-b}{a+b}=\frac{c-d}{c+d};\)
b,\(\frac{2a+5b}{3a-4b}=\frac{2c+5d}{3c-4d};\)
c,\(\frac{ab}{cd}=\frac{\left(a-b\right)^2}{\left(c-d\right)^2};\)
Chứng minh:
a) \(\frac{a}{3a+b}=\frac{c}{3c+d}\)
b)\(\frac{a^2-b^2}{c^2-d^2}=\frac{ab}{cd}\)