a
\(V _{0}( t )= V _{\text {in }}\left(1- e ^{\frac{ t }{ RC }}\right)\)

at \(t =5 \mu s\)

\(V _{0}( t )=5\left(1- e ^{-\frac{5 \times 10^{-6}}{10^{3} \times 10 \times 10^{-9}}}\right)\)

\(=5\left(1- e ^{-0.5}\right)=2 V\)

Now \(V_{\text {in }}=0\) means discharging

\(V _{0}( t )=2 e ^{-\frac{ t }{ RC }}=2 e ^{-0.5}\)

\(=1.21 V\)

Now for next \(5 \mu s\)

\(V _{0}( t )=5-3.79 e ^{-\frac{t}{ RC }}\)

after \(5 \mu s\) again

\(V _{0}( t )=2.79 Volt \approx 3 V\)