beta distribution

x <- seq(0, 1, length = 100)#生成100个（0，1）之间的数值

plot(dbeta(x,1,10))#严格递减 a=1，b>1

 plot(dbeta(x,10,1))))#严格递增 a>1，b=1 
plot(dbeta(x,0.5,0.5))#a<1,b<1

 plot(dbeta(x,5,5))#a>1,b>1单峰

plot(dbeta(x,1,1))#a=1，b=1均匀分布