how to plot tail of normal distribution

would like to see the shape of tail of distribution

why system inconsistent 

when only want to obtain a equation H

in terms of a1 , a3, b2, b3, c1, c2, x1, x2, lambda

pdsolve([
Diff(H(x1,x2,lambda), x1) = a1*x1 + a3*lambda,
Diff(H(x1,x2,lambda), x2) = b2*x2 + b3*lambda,
Diff(H(x1,x2,lambda), lambda) = c1*x1 + c2*x2
], H(x1,x2,lambda));

with(Finance):
with(Statistics):
X:=RandomVariable(Binomial(nn, pp));
Drift(X);

How to listplot two vectors on the same graph?

That means having two lines.

f1 := -2*x1 - x2;
f2 := -x1 - 4*x2;
g1 := 2*x1 + 3*x2 - 6;
g2 := -x1;
g3 := -x2;
penalty := lambda1*Max(f1-M,0)+lambda2*Max(f2-M,0)+(M^2)*(max(g1,0) + max(g2,0) + max(g3,0));
M := 1;
k := 1;
s := 1;
lambda1 := 0.5;
lambda2 := 0.5;
with(Optimization):
Minimize(subs(lambda2=0.5, subs(lambda1=0.5, subs(M=1, penalty))));

correct answer for these parameters should be below, however, Minimize got error

when lambda1 = 0.5, lambda2 = 0.5
(x1, x2) = 1.551123, 0.965918
f(x1, x2) = (–4.068164, –5.414795);