có thể chứng minh mà ko phải đặt k ko
có thể chứng minh mà ko phải đặt k ko
a) tìm x, biết: x = \(\frac{a}{b+c}\)= \(\frac{b}{c+a}\)= \(\frac{c}{a+b}\)
b) cho \(\frac{a}{b}\)= \(\frac{c}{d}\). CMR: \(\frac{4a^4+5b^4}{4c^4+5d^4}\)= \(\frac{a^2b^2}{c^2d^2}\)
Cho a/b=c/d
a)a/a+c=b/b+d
b)a+c/b+d=a-c/b-d
c)a/c=a+b/c+d
d)4a^4+5b^4/4c^4+5d^4=a^2b^2/c^2d^2
Cho \(\frac{a}{b}=\frac{c}{d}\). Chứng minh:
a) \(\frac{\left(a-b\right)^3}{\left(c-d\right)^3}=\frac{3a^2+2b^2}{3c^2+2d^2}\)
b)\(\frac{4a^4+5b^4}{4c^4+5d^4}=\frac{a^2b^2}{c^2d^2}\)
c)\(\left(\frac{a-b}{c-d}\right)^{2005}=\frac{2a^{2005}-b^{2005}}{2c^{2005}-d^{2005}}\)
d)\(\frac{2a^{2005}+5b^{2005}}{2c^{2005}+5d^{2005}}=\frac{\left(a+b\right)^{2005}}{\left(c+d\right)^{2005}}\)
e)\(\frac{\left(20a^{2006}+11b^{2006}\right)^{2007}}{\left(20a^{2007}-11b^{2007}\right)^{2006}}=\frac{\left(20c^{2006}+11d^{2006}\right)^{2007}}{\left(20c^{2007}-11d^{2007}\right)^{2006}}\)
f)\(\frac{\left(20a^{2007}-11c^{2007}\right)^{2006}}{\left(20a^{2006}+11c^{2006}\right)^{2007}}=\frac{\left(20b^{2007}-11d^{2007}\right)^{2006}}{\left(20b^{2006}+11d^{2006}\right)^{2007}}\)
cho \(\frac{a}{b}\)=\(\frac{c}{d}\)cmr:\(\frac{4a^4+5b^4}{4c^4+5d^4}\)= \(\frac{a^2.b^2}{c^2.d^2}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\). Chứng minh:
1) \(\dfrac{2a+3c}{2b+3d}=\dfrac{2a-3c}{2b-3d}\)
2) \(\dfrac{4a-3b}{4c-3d}=\dfrac{4a+3b}{4c+3d}\)
3) \(\dfrac{3a+5b}{3a-5b}=\dfrac{3c+5d}{3c-5d}\)
4) \(\dfrac{3a-7b}{b}=\dfrac{3c-7d}{d}\)
Chứng minh \(\frac{4a+2b}{4c+2d}=\frac{7a-5b}{7c-5d}\) \(=\frac{a}{b}=\frac{c}{d}\)
cho \(\frac{a}{b}=\frac{c}{d}cm:\frac{4a-5b}{4a+5b}=\frac{4c-5d}{4c+5d}\)
giúp mình nha
Cho \(\frac{a}{b}\)= \(\frac{c}{d}\),chứng minh rằng:
a.\(\frac{4a-3b}{4c-3d}\)=\(\frac{4a+3b}{4c+3d}\)
b.\(\frac{a^2-b^2}{a.b}\)=\(\frac{c^2-d^2}{c.d}\)
c.\(\frac{a-b}{c-d}\)=\(\frac{2a+5b}{2c+5d}\)
CÁC BN ƠI GIÚP MK ĐI MK ĐANG CẦN GẤP.
cho a/b = c/d chung minh :
4a^2 + 5b^4 / 4c^4 + 5d^4 = a^2 x b^2 / c^2 x d^2