1.
[tex]a)\\T = 0,005 \ s\\\\f = \frac{1}{T} = \frac{1}{0,005 \ s} = 200 \ Hz\\\\b)\\T = 0,06 \ s\\\\f = \frac{1}{T}=\frac{1}{0,06 \ s} = 16,7 \ Hz\\\\c)\\T = 20 \ s\\\\f = \frac{1}{T} = \frac{1}{20 \ s} = 0,05 \ Hz[/tex]
2.
[tex]f = 60 \ Hz = 60 \ \frac{1}{s}\\\\T = \frac{1}{f} =\frac{1}{60 \frac{1}{s}} = 0,017 \ Hz[/tex]