6a^2b^2" alt="a^4 + 2a^3b + 2ab^3 + b^4 > 6a^2b^2" align="absmiddle" class="latex-formula">
0" alt="a^4 - 2a^2b^2 + b^4 + 2a^3b - 4a^2b^2 + 2ab^3>0" align="absmiddle" class="latex-formula">
0" alt="(a^2 - b^2)^2 + 2ab(a^2 - 2ab + b^2)>0" align="absmiddle" class="latex-formula">
0" alt="(a^2 - b^2)^2 + 2ab(a - b)^2 >0" align="absmiddle" class="latex-formula">
a и b - одного знака, значит
0" alt="a*b>0" align="absmiddle" class="latex-formula">, тогда
0" alt="(a^2 - b^2)^2 + 2ab(a - b)^2 >0" align="absmiddle" class="latex-formula">