For positive real numbers a,b,c
Prove that:
[tex]3.\frac{a^2+b^2+c^2}{a+b+c} \geq \frac{a^2+b^2}{a+b}+\frac{b^2+c^2}{b+c}+\frac{c^2+a^2}{c+a} [/tex]
[tex]a,b,c \geq 0[/tex]
[tex]\frac{1}{(1+\sqrt{a})^2}+\frac{1}{(1+\sqrt{b})^2} \geq \frac{2}{2+a+b}[/tex]
[tex]a,b,c>0[/tex]
[tex]a+b+c=1[/tex]
[tex]\frac{1}{a+bc+3abc} +\frac{1}{b+ca+3abc}+\frac{1}{c+ab+3abc} \geq \frac{2}{ab+bc+ca+abc}[/tex]
[tex]a,b,c>0[/tex]
[tex](\frac{1}{a}+\frac{1}{b}+\frac{1}{c}).(\frac{1}{a+1}+\frac{1}{b+1}+\frac{1}{c+1}) \geq \frac{9}{abc+1}[/tex]
[tex]a \geq b \geq c \geq 0[/tex]
[tex]\frac{a^2b}{c}+\frac{b^2c}{a}+\frac{c^2a}{b} \geq 2.(a^2+b^2+c^2)-ab-bc-ca[/tex]
[tex]a,b,c>0[/tex]
[tex]\frac{a^2+1}{(a+b).(c+a)}+\frac{b^2+1}{(b+c).(b+a)}+\frac{c^2+1}{(c+a).(c+b)} \geq \frac{(\sqrt{a}+\sqrt{b}+\sqrt{c})^2}{2.(a^2+b^2+c^2)}[/tex]
[tex]a,b,c \geq 0[/tex]
[tex]\frac{a^4}{b^2+bc+c^2}+\frac{b^4}{c^2+ca+a^2}+ \frac{c^4}{a^2+ab+b^2} \geq \frac{a^3+b^3+c^3}{a+b+c}[/tex]
[tex]a,b,c>0[/tex]
[tex]\frac{a^3}{2a^2+b^2}+\frac{b^3}{2b^2+c^2}+\frac{c^3}{2c^2+a^2} \geq \frac{a+b+c}{3}[/tex]
[tex]a,b,c>0[/tex]
[tex]2.(a+b+c).(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}) \geq (4-\frac{ab+bc+ca}{a^2+b^2+c^2})^2+\frac{9}{4}[/tex]