voi a,b,c,d, la cac so duong thoa man a*b = c*d =1 chung minh bat dang thuc : ( a+b )*( c+d ) +4 >= 2*( a+b+c+d ) cac ban oi giup minh voi OK

cac ban giai giup minh bai tap nay khan cap nhe:

cho cac so a,b,c la ba so nguyen khac 0, thoa man: ab/(a+b)=bc/(b+c)=ac/(a+c) ( gia thiet cac ti le thuc deu co nghia). tinh M= (ab + bc + ca)/(a^2+b^2+c^2)

xin cam on rat nhieu

cho a,b,c la cac so thoa man a^2+b^2+c^2=<8 tim GTNN cua xy+yz+2xz

Cho a, b, c, d la cac so nguyen duong  thoa man a²+b²=b²+d². CM a+b+c+d la hop so

cho a,b,c la cac so thoa man (a+1)^2+(b+2)^2+(c+3)2<2010.tim GTNN cua bieu thuc A=ab+b(c-1)+c(a-2)

cho a,b,c la cac so nguyen thoa man a+b+c+ab+bc+ca=6. chung minh rang a^2+b^2+c^2 khong nho hon 3

1. Cho a,b,c,d la cac so nguyen thoa man \(a^2=b^2+c^2+d^2\)

chung minh rang a.b.c.d + 2015 viet duoc duoi dang hieu cua 2 so chinh phuong.

2. Cho a,b la cac so duong thoa man dieu kien a+b=1. tim gia tri nho nhat cua bieu thuc

\(P=\frac{2+a}{\sqrt{2-a}}+\frac{2+b}{\sqrt{2-b}}\)

cho a b c la cac so nguyen khac 0 thoa man ab - ac + bc = c^2 -1. khi do a/b bang bn

cho cac so duong a,b,c thoa man (a^2+b^2+c^2)^2>2*(a^4+b^4+c^4)

cm rang a,b,c la do dai ba canh cua tam giac.