от Nathi123 » 19 Дек 2016, 20:18
[tex]f(x) = x^{2}+\frac{a^{4}}{4 x^{2}}-\frac{a^{2}}{2}= x^{2}+\frac{a^{4}}{4}.x^{-2}-\frac{a^{2}}{2}[/tex]
[tex]\Rightarrow f'(x) = 2x -\frac{a^{4}}{2}.x^{-3}=2x-\frac{a^{4}}{2x^{3}}[/tex], защото :
[tex](x^{2}) '=2x; ( \frac{a^{4}}{4}.x^{-2}) '= -\frac{a^{4}}{4}2x^{-3} ; x^{-3}=\frac{1}{x^{3}} ; (-\frac{a^{2}}{2}) '= 0[/tex]