//chapter 3
// example 3.15
//page 148
// Vout=-(3Vin1+4Vin2+5Vin3)
Rf=120*10^3;
// for inverting summer we have Vout=-(Rf/R1Vin1+Rf/R2Vin2+Rf/R3Vin3)
R1=Rf/3;//Rf/R1=3  comparing the cofficients
disp(R1)
R2=Rf/4;
disp(R2)
R3=Rf/R3;
disp(R3)