h = 0.85;
sig = 2;
bet = 0.99;
et = 1;

a = h*sig/((1-bet*h)*(1-h));
b = et + (sig/((1-bet*h)*(1-h)))*(1+bet*h^2);

delta_2 = b/(2*a*bet) - sqrt( (b/(2*a*bet))^2 - 1/bet )

