tim tat ca cac so duong a,b,c thoa man dieu kien \(\left\{{}\begin{matrix}\sqrt{a}+\sqrt{b}+\sqrt{c}=6\\\frac{1}{\sqrt{a}}+\frac{4}{\sqrt{b}}+\frac{9}{\sqrt{c}}=6\end{matrix}\right.\)

Tim cac so nguyen duong a, b, c thoa man: \(\left\{{}\begin{matrix}\sqrt{a-b+c}=\sqrt{a}-\sqrt{b}+\sqrt{c}\\\dfrac{1}{a}+\dfrac{1}{b}+\dfrac{1}{c}=1\end{matrix}\right.\)

cho 3 so thuc duong a ,b ,c thoa man a+b+c = 12 . CMR

\(\sqrt{3a+2\sqrt{a}+1}+\sqrt{3b+2\sqrt{b}+1}+\sqrt{3c+2\sqrt{c}+1}\le3\sqrt{17}\) 

cho cac so a,b,c duong thoa man ab+bc+ca=1  chung minh : \(p=\frac{2a}{\sqrt{1+a^2}}+\frac{b}{\sqrt{1+b^2}}+\frac{c}{\sqrt{1+c^2}}\)

cho so thuc a,b,c voi a ,b duong va c\(\ne\)0 thoa man

\(\dfrac{1}{a}+\dfrac{1}{b}+\dfrac{1}{c}=0\)

1/chung minh c<0 , a+c>0 va b+c >0

2/chung minh \(\sqrt{a+b}=\sqrt{a+c}+\sqrt{b+c}\)

cho ca so a,b,c duong thoa man ab+bc+ca =1  chung minh   \(P=\frac{2a}{\sqrt{1+a^2}}+\frac{b}{\sqrt{1+b^2}}+\frac{c}{\sqrt{1+c^2}}\le\frac{1}{4}\)

1)Rut gon bieu thuc:P=\(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}\)

2) Cho 3 so duong a,b,c thoa man dieu kien:a+b+c=\(\sqrt{ab}+\sqrt{bc}+\sqrt{ca}\)

Chung minh rang:a=b=c

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 cac so thuc phan a,b,c khac nhau doi mot va thoa man a^2-b=b^2-c=c^2-a . CMR (a+b+1)()b+c+1(c+a+1)=-1- de hsg tinh mon toan 9 nam 2012