cho tỉ lệ thức\(\dfrac{a}{b}=\dfrac{c}{d}\)
(a,b,c,d khác 0)
chứng tỏ rằng
bài 1 \(\dfrac{a}{a+c}=\dfrac{b}{b+d}\)
bài 2 \(\dfrac{2a+c}{3a-c}=\dfrac{2b+d}{3b-d}\)
bài 3\(\dfrac{5a-2c}{3a-4c}=\dfrac{5b-2d}{3b-4d}\)
nhanh nha gấp lắm ạ
Cho dãy tỉ số bằng nhau:
\(\dfrac{2a+b+c+d}{a}=\dfrac{a+2b+c+d}{b}=\dfrac{a+b+2c+d}{c}=\dfrac{a+b+c+2d}{d}\)
Tính : \(M=\dfrac{a+b}{c+d}+\dfrac{b+c}{d+a}+\dfrac{c+d}{a+b}+\dfrac{d+a}{b+c}\)
Cho tỉ lệ thức \(\dfrac{a}{b}=\dfrac{c}{d}\). Hãy chứng minh rằng :
\(\dfrac{a}{a+b}=\dfrac{c}{c+d}\)
\(\dfrac{a+2c}{b+2d}=\dfrac{a-2c}{b-2d}\)
\(\dfrac{a^2+2b^2}{c^2+2d^2}=\dfrac{a^2-2b^2}{c^2-2d^2}\)
\(\dfrac{ab}{cd}=\dfrac{\left(a+b\right)^2}{\left(c+d\right)^2}\)
Câu 1: Cho \(\dfrac{a^{2016}+b^{2016}}{c^{2016}+d^{2016}}=\dfrac{a^{2016}-b^{2016}}{c^{2016}-d^{2016}}\). Chứng minh: \(\dfrac{a}{b}=+-\dfrac{c}{d}\)
Câu 2: Cho dãy tỉ số bằng nhau: \(\dfrac{2a+b+c+d}{a}=\dfrac{a+2b+c+d}{b}=\dfrac{a+b+2c+d}{c}=\dfrac{a+b+c+2d}{d}\). Tính giá trị biểu thức: M = \(\dfrac{a+b}{c+d}+\dfrac{b+c}{d+a}+\dfrac{c+d}{a+b}+\dfrac{d+a}{b+c}\)
Câu 3: Tìm x, y ϵ N biết: \(25-y^2=8\left(x-2009\right)^2\)
Câu 4: Tìm x biết: \(\left|x^2+\left|6x-2\right|\right|=x^2+4\)
Câu 5: Tìm các số nguyên thoả mãn: \(x-y+2xy=7\)
Câu 6: Cho \(a>2,b>2\). Chứng minh: \(ab>a+b\)
Cho dãy tỉ số bằng nhau :
\(\dfrac{a}{b+c+d}=\dfrac{b}{a+c+d}=\dfrac{c}{a+b+d}=\dfrac{d}{b+c+a}\)
Tìm giá trị của biểu thức
\(M=\dfrac{a+b}{c+d}+\dfrac{b+c}{a+d}+\dfrac{c+d}{a+b}=\dfrac{d+a}{b+c}\)
Cho ad = bc và a, b, c, d khác 0. Chứng tỏ rằng:
a) \(\dfrac{a}{b}\) = \(\dfrac{c}{d}\) b) \(\dfrac{a+c}{b+d}\) = \(\dfrac{a}{b}\) c) \(\dfrac{a}{c}\) = \(\dfrac{b}{d}\) d) \(\dfrac{a+b}{b}\) = \(\dfrac{c+d}{d}\) e) \(\dfrac{2a+b}{2c+d}\) = \(\dfrac{a}{c}\)
Cho \(\dfrac{a}{b}=\dfrac{c}{d}\). CMR \(\dfrac{a}{2a+c}=\dfrac{b}{2b+d}\)
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
1. Cho \(\dfrac{a}{b}\) = \(\dfrac{c}{d}\) c/m
a) (2a+3c) . (2b-3d) = (2a- 3c) . (2b+3d)
b) \(\dfrac{\left(a^2+c\right)^2}{\left(b+d\right)^2}\) = \(\dfrac{\left(a-c\right)^2}{\left(b-d\right)^2}\)
c)\(\dfrac{a^3+b^3}{c^3+d^3}\) = \(\dfrac{a^3-b^3}{c^3-d^3}\)
d) \(\dfrac{a^{2018}-b^{2018}}{a^{2018}+b^{2018}}\) = \(\dfrac{c^{2018}-d^{2018}}{c^{2018}+d^{2018}}\)
HELP ME >~< !!!