//chapter 2
//example 2.1
//page 37
printf("\n")
printf("given")
disp("a)")
If=100*10^-3;Vf=.75;//given
disp("forward resistance")
Rf=Vf/If;
printf("forward resistnace is %3.1fohm\n",Rf)
disp("b)")
Vr=50;Ir=100*10^-9;
Rr=(Vr/Ir);
printf("reverse resistnace is %3.0fohm\n",Rr)