1/ cho \(\frac{a}{b}=\frac{c}{d}\)chứng minh rằng:
a) \(\frac{a.b}{c.d}=\frac{\left(a+b\right)^2}{\left(c+d\right)^2}\)
b)\(\frac{a,d}{c.b}=\frac{\left(a+b\right).\left(a-b\right)}{\left(c+d\right).\left(c-d\right)}\)
2/ cho \(a.b=c^2\)chứng minh : \(\frac{a}{b}=\frac{\left(2a+3c\right)^2}{\left(2c+3b\right)^2}\)
Cho\(\frac{a}{b}=\frac{c}{d};\left(a,b,c,d,\right)\)chứng minh\(\frac{a.b}{c.d}=\frac{\left(a+b\right)^2}{\left(c+d\right)^2}\)
Rút gọn các Biểu Thức sau
a)\(\frac{a^2m-a^2n-b^2n+b^2m}{a^2+b^2}\)
b)\(\frac{\left(ab+bc+cd+da\right)abcd}{\left(c+d\right)\left(a+b\right)+\left(b-c\right)\left(a-d\right)}\)
cho a/b = c/d . tính \(\frac{a.b}{c.d}+\left[\left(\frac{a+b}{c+d}\right)^2:\left(\frac{a^2+b^2}{c^2+d^2}\right)\right]-\frac{a^2-b^2}{c^2-d^2}\)
\(\frac{a.b}{c.d}=\frac{\left(a-b\right)^2}{\left(c-d\right)^2}\)
Cho \(\frac{a}{b}\)= \(\frac{c}{d}\)(a,b,c,d # 0) Chứng minh răng\(\frac{\left(a+b\right).\left(a-b\right)}{\left(c+d\right).\left(c-d\right)}\)= \(\frac{a.b}{c.d}\)
Cho
\(\frac{a}{b}=\frac{c}{d}\) Chứng minh \(\frac{a.b}{c.d}=\frac{\left(a+b\right)^2}{\left(c+d\right)^2}\)
Cho tỉ lệ thức: \(\frac{a}{b}=\frac{c}{d}\).Chứng minh:
\(\frac{a.b}{c.d}=\frac{a^2+b^2}{c^2+d^2}\); \(\frac{\left(a+b\right)^3}{\left(c+d\right)^3}=\frac{a^3+b^3}{c^3+d^3}\)
Cho \(\frac{a}{b}\)= \(\frac{b}{c}\)= \(\frac{c}{d}\)= \(\frac{d}{a}\). Tính M = \(\frac{\left(a+b\right)\left(b+c\right)\left(c+d\right)\left(d+a\right)}{a.b.c.d}\)