t <- seq(from=-3,to=3,by=0.01)
plot(t,dnorm(t),ylab="PDF")
plot(t,pnorm(t),ylab="PDF")
这个是画简单的PDF和CDF图，现在又如下要求：
plotthe probability density function and cumulative distribution function(Prob(T)<t) for the t-distribution with infinity, 10 and 1 degree offreedom.Make the y-limit of the first and second figure rangefrom 0 to 0.5 and 0 to 1 respectively. Make sure the main title is in a fonttwice the default size, the y-axes are labeled as shown, and the line types 1,2and 3 correspond to the t-distribution with Inf, 10 and 1 degree of freedomrespectively.
标题和两个坐标轴有一些要求，这个较好实现，但是在一张图上实现3个不同的自由度的绘图，然后要怎么实现呢，效果图如下所示：
前辈们，在具体的函数中要用到哪些参数，能指教一下吗，谢谢