$4).$ Let Vt $=2$V$,$ k n $($W$/$L$)=1$mA$/$V$2,$ Vsig is an AC source. MOSFET$-1$ has DC values:

VGS$=3$V$,$ ID$=0\mathrm{.}5$mA$,$ MOSFET$-2$ has DC values: VGS$=5$V$,$ ID$=4\mathrm{.}5$mA$.$ $=0($for all

transistors$)$ and assume all transistors are saturated.