//chapter 14
//example 14.9
//page 612
printf("\n")
printf("given")
Acl=3;R4=1*10^6;Vi=1;
R1=R4/Acl
R1=330*10^3;//use standard value 
R2=R1;R3=R1;
I1=Vi/R1
I2=I1;I3=I1;
I4=I1+I2+I3
Vo=-I4*R4