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 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
cho a,b,c,d thuoc Z va 0<a<b<c<d chung minh rang neu a/bc/d thi a+d>b+c
cho so huu ti a/b voi b>0. chung to rang
neu a/b<1 thi a<b va nguoc lai neu a<b thi a/b <1
giup minh voi
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
chung to rang neu a/b<c/d (b,d>0) thi a/b < a+c/b+d < c/d
cho hai so huu ti a/b va c/d voi mau duong, trong do a/b < c/d . chung minh rang :
a . ad < bc b . a/b < a+c / b+d < c/d
giup mk nha
CMR: neu a,b,c,d thoa man dang thuc: (ad+bc)^2= 4abcd thi chung lap nen 1 ti le thuc