有人能
clear;clc
for j=1:1000
p=j/1000;
for i=0:9
A1(i+1)=nchoosek(10+i,i)*(1-p)^i;
A2(i+1)=p^i*(1-p)^i*p;
end
A(j)=p^11*sum(A1)+nchoosek(20,10)*p^11*(1-p)^10*sum(A2);
for i=0:19
B1(i+1)=nchoosek(10+i,i)*(1-p)^i;
B2(i+1)=p^i*(1-p)^i*p*p;
end
B(j)=p^21*sum(B1)+nchoosek(40,20)*p^21*(1-p)^20*sum(B2);
end
plot([1:1000]/1000,[A;B])
text(0.5,A(500),'A')
text(0.5,B(500),'B')