clear;
close all;
home;
vp=-7;
idss=10e-3;
a = idss/vp^2;
b = 1/2000-2*idss/vp;
c = -6/2000+idss;
ans1 = (-b+sqrt(b^2-4*a*c))/(2*a)  %<--this one is correct
ans2 = (-b-sqrt(b^2-4*a*c))/(2*a)

idq = idss*(1-ans1/vp)^2*1000

vgs = linspace(-7,0,501);
idq1 = (6-vgs)/2e3;
idq2 = idss*(1-vgs/vp).^2;
plot(vgs,idq1,vgs,idq2)
%axis([0 10 0 200e-3])