[tex]log_ \frac{1}{ \sqrt{5}} \sqrt{125} [/tex]
[tex] \sqrt{125} = 125^{ \frac{1}{2} } = 5^{ \frac{3}{2} } [/tex]
[tex] \frac{1}{ \sqrt{5} } = \frac{1}{ 5^{ \frac{1}{2} } } = 5^{- \frac{1}{2} }[/tex]
[tex]log_{a^{b}} c^d [/tex] = [tex] d * \frac{1}{b} log_a c[/tex] Deci vom avea
[tex] \frac{3}{2} *(-2) log_5 5 [/tex] = -3