Question$5[12$ marks$]$

I. $[4]$ For the non$-$inverting amplifier in Fig. $5$a show $\frac{v_o}{v_i}=(1+\frac{R_f}{R_1})$

II$.[8]$ Find the voltage $v_o$ in Fig. $5$b$.($Hint: inverting amplifier $\frac{v_o}{v_i}=-\frac{R_f}{R_1})$

Fig $5$a

Fig $5$b