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 voi a,b thuoc Z, b>0. Chung minh rang: neu co a<b va >0 thi a/b<a+c/b+c
cac ban cho minh hoi
chung to rang neu a/b<c/d (b>0,d>0) thi a/b<a+c/b+d<c/d
cho ti le thuc voi a,b,c,d thuoc z b,d khac 0 chung minh rang a^2 + b^2 phần c^2 + d^2 =a*b phần 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 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 thuoc Z b;d;c>0 .CMR:
Neu a>b thi a/b>a+c/b+c
Neu a<b thi a/b<a+c/b+c
chung to rang neu a/b<c/d (b,d>0) thi a/b < a+c/b+d < c/d
Cho a = b + c va c = bd/b -d ( b , d khac 0 ) .chung minh rang a/b = c/d
