png("c:\\plot\\beta_dist.png", width = 1024*1.3, height = 768*1.3)

par(mfrow=c(4,9))

for(a in alpha){
    for(b in beta){
        y <- dbeta(x, a, b)
        plot(x, y, type="l", ylab=paste0("a=",a), main=paste0("b=", b))
        print(paste(a, ", ", b))
    }
}

par(mfrow=c(1,1))
dev.off()