This is the result from a lab,but I am not sure the results are correct. Also,when I try to find I(c) , I(b) and I(e),by measured V(RC) and V(RE),I find the results strange. I guess the combination of R1=10k and R2=10k is under linear region,but the dc gain is so small. For combination of R1=10k and R2=1k,Idon't know why the I(b) is negative.Is it the cut off mode? And for combination of R1=1k and R2=10k,it should be in saturation? I guess R2 is like a battery so current I(b) flow ,but how about R1??