Think about this. You first stated that if Vs=13V that if Is=0mA that Vout would be 13V, so one of the points would be (13V,0mA). You then stated that if Vout is 0 that Is=Vs/R1 which would make Is=13mA. So another point would be (0V, 13mA). Then you noted that if Is=1mA that Vout would be 12V, giving you the point (12V, 1mA). How do you then come up with your final conclusion?Ok, so if Vs=13V and Is=0mA, I know Vout = Vs-IsR1=Vs
Now, for 2nd part if Vout is zero, Is=Vs/R1
And if I use condition for Q1 as Is=1ma, i would get a point of 12V
so my graph for Vout vs Is would just be essentially y=x, as for w/e conditions i will get pts that are (13V,13mA),(13.5v,13.5mA) etc.