needle.m

一些常被用于教学或者参考的概率论的实例的源代码

%needle.m/created by PJNahin for "Duelling Idiots"(1/13/99)
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ratio=(0:.01:1);
factor1=asin(ratio);
factor2=sqrt(1-ratio.^2);
prob1=1-(2/pi)*(ratio.*factor2+factor1);
factor3=sqrt(1-.25*ratio.^2);
factor4=asin(.5*ratio);
prob3=(2/pi)*(ratio.*factor3+2*factor4-ratio.*factor2-factor1);
prob2=1-(prob1+prob3);
figure(1)
plot(ratio,prob1)
xlabel('a/r')
ylabel('probability')
grid
title('Fig.11.3-Probability Neither End of Needle Sticks-Out Over Edge')
figure(2)
plot(ratio,prob2)
xlabel('a/r')
ylabel('probability')
grid
title('Fig.11.4-Probability One End of Needle Sticks-Out Over Edge')
figure(3)
plot(ratio,prob3)
xlabel('a/r')
ylabel('probability')
grid
title('Fig.11.5-Probability Both Ends of Needle Stick-Out Over Edge')