cho a,b la so thuc duong thoa man:a^2+2ab+2b^2-2b=8. cm 0<a+b<=3
Cho 2 so duong a,b thoa man \(\frac{1}{a}+\frac{1}{b}=2\)
Tim GTLN cua bieu thuc A=\(\frac{1}{a^4+b^2+2ab^2}+\frac{1}{b^4+a^2+2a^2b}\)
cho a,b,c la cac so thuc thoa man a+2b-3b=0 va bc +2ac-3ab=o.chung minh a=b=c
cho a,b,c la cac so thuc thoa man a+2b-3b=0 va bc +2ac-3ab=o.chung minh a=b=c
cho a+b+c=0 cm n=1-(ab+2c^2)(bc+2a^2)(ca+2b^2) la not so duong
cho a , b, c la cac so thuc duong thoa man he thuc a+b+c=6abc
Chung minh rang \(\dfrac{bc}{a^3\left(c+2b\right)}+\dfrac{ac}{b^3\left(a+2c\right)}+\dfrac{ab}{c^3\left(b+2a\right)}\ge2\)
Cho 2 so thuc duong a,b thoa man a+b<=1.Tim GTNN cua
\(A=\frac{1}{a^3+b^3}+\frac{1}{a^2b}+\frac{1}{ab^2}\)
cho a,b,c la 3 so thuc thoa man dk: a^2=(b-c)^2+2 va a^2= (b+c)^2-6.
tinh gia tri cua bieu thuc A=4a^2b^2-(a^2+b^2-c^2)^2
cho a,b,c la cac so thuc duong. chung minh rang 2a/(b+c)+2b/(c+a)+2c/(a+b)>=((a-b)^2+(b-c)^2+(c-a)^2)/(a+b+c)^2
so cap so nguyen duong (a;b) thoa man a+2b=11 la