Các câu hỏi tương tự
Cho hai so huu ti a/b va c/d (b>0, d>0). Chung to rang :
a, Neu a/b < c/d thi ad<cd
b, Neu ad<bc thi a/b < c/d
cho so huu ti a/b va c/d voi b>0 chung to rang neu a/b > c/d thì a/b<a+c/b+d <c/d
cho a, b, c, d khac 0 va thoa man
ac=b^2; bd=c^2
chung minh \(\frac{a^3+b^3+c^3}{b^3+c^3+d^3}=\frac{a}{d}\)
cho \(\frac{a}{b}\)=\(\frac{c}{d}\) chung minh \(\frac{3a^6+c^6}{3b^6+d^6}\)=\(\frac{\left(a+c\right)^6}{\left(b+d\right)^6}\) va b+d khac 0
cho a, b, c, d la 4 so nguyen duong thoa man: b= \(\frac{a+c}{2}va\frac{1}{c}=\frac{1}{2}.\left(\frac{1}{b}+\frac{1}{d}\right)\)
chung minh: \(\frac{a}{b}=\frac{c}{d}\)
cho \(\frac{a}{b}\)<\(\frac{c}{d}\)(b>0,d>0)
chung minh :\(\frac{a}{b}\)<\(\frac{a+c}{b+d}\)<\(\frac{c}{d}\)
chung minh rang ty le thuc\(\frac{a}{b}\)=\(\frac{c}{d}\)(a-b khong =0,c-d khong =0) ta co the suy ra ti le thuc \(\frac{a+b}{a-b}\)=\(\frac{c+d}{c-d}\)
a)Chung to rang neu a/b <c/d (b<0,d<0) thi a/b < a+c/d+b < c/d
b)Hay viet 3 so huu ti xen giua -1/3 va -1/4
cho ti le thuc \(\frac{a}{b}\)=\(\frac{c}{d}\)
chung minh rang\(\frac{a}{b}\)=\(\frac{7a+5c}{7b+5d}\)[b+d khac 0]
cac ban co biet tai sao minh go dau cac chu cai thi chu cai do va dau deu bien mat khong? giup minh voi , cau hoi tren la 1 vi du