Cho \(\frac{a}{b}\)= \(\frac{c}{d}\). CTR :
a) \(\frac{a}{b}\)= \(\frac{3a+2c}{3b+2d}\) ( 3b + 2d # 0)
b) \(\frac{a^2+c^2}{b^2+d^2}\)= \(\frac{ac}{bd}\)
Cho \(\frac{a}{b}=\frac{c}{d}\) . Chứng tỏ \(\frac{a}{b}=\frac{3a+2c}{3b+2d}\)
\(\frac{a}{b}=\frac{c}{d}=\frac{3a}{3b}=\frac{2c}{2d}=\frac{3a+2c}{3b+2d}\)
Cho \(\frac{a}{b}=\frac{c}{d}\)Chứng minh rằng : \(\frac{a-c}{b-d}=\frac{3a+2d}{3b+2d}\)
Áp dụng tỉ lệ thức => a/b=c/d=(a-c)/(b-d) (1)
ta có : a/b=c/d
=> 3a/3b=2c/2d=(3a+2c)/(3b+2d) (2)
Từ(1)(2)=> (a-c)/(b-d)=(3a+2c)/(3b+2d) (điều phải chứng minh)
cho \(\frac{a}{b}=\frac{c}{d}\). Chứng minh rằng \(\frac{3a+2c}{3b+2d}=\frac{-5b+3c}{-5d+3d}\)
A)\(CMR:\frac{a+2c}{b+2d}\)\(=\frac{3a+c}{3b+d}\)
B)\(CMR:\frac{a-c}{a+3c}=\frac{b-d}{b+3d}\)
A)\(CMR:\frac{a+2c}{b+2d}\)\(=\frac{3a+c}{3b+d}\)
B)\(CMR:\frac{a-c}{a+3c}=\frac{b-d}{b+3d}\)
A)\(CMR:\frac{a+2c}{b+2d}\)\(=\frac{3a+c}{3b+d}\)
B)\(CMR:\frac{a-c}{a+3c}=\frac{b-d}{b+3d}\)
Nếu a= \(\frac{bc}{d}.cm:a=\frac{b\left(3a+2c\right)}{3b+2d}\)
Ta có : \(a=\frac{bc}{d}\Rightarrow\frac{a}{b}=\frac{c}{d}\)\(=k\)
\(\Rightarrow k=\frac{3a}{3b}=\frac{2c}{2d}\)
\(\Rightarrow k=\frac{3a+2c}{3b+2d}\)
Do đó : \(\frac{a}{b}=\frac{3a+2c}{3b+2d}\)
\(\Rightarrow a=\frac{b\left(3a+2c\right)}{3b+2d}\)
Áp dụng dãy tỉ số bằng nhau:
\(a=\frac{bc}{d}\Rightarrow\frac{a}{b}=\frac{c}{d}=\frac{3a}{3b}=\frac{2c}{2d}=\frac{3a+2c}{3b+2d}\)
\(\Rightarrow\frac{a}{b}=\frac{3a+2c}{3b+2d}\Rightarrow a=\frac{b\left(3a+2c\right)}{3b+2d}\)
Cho tỉ lệ thức \(\frac{a}{b}=\frac{c}{d}=\frac{3a+2c}{3b+2d}\) chứng minh tỉ lệ thức sau
Cho tỉ lệ thức: \(\frac{a}{b}=\frac{c}{d}\)
CMR: \(\frac{3a+2c}{3b+2d}=\frac{-5a+3c}{-5b+3d}\)
Áp dụng tính chất DTS bằng nhau:
\(\frac{a}{b}=\frac{c}{d}=\frac{3a}{3b}=\frac{2c}{2d}=\frac{3a+2c}{3b+2d}\)
\(\frac{a}{b}=\frac{c}{d}=\frac{-5a}{-5b}=\frac{3c}{3d}=\frac{-5a+3c}{-5b+3d}\)
Vậy....