title: How to draw the true density (for the specified gamma distribution) on histogram
body: <p>I want to draw the true density on histogram.
  Here is my code, I'm not sure if my codes are right or not.</p>
  
  <pre><code>set.seed(600)
  x &lt;- rgamma(500,shape=8,scale=0.1)
  mean(x)
  hist(x,prob=T,main='Gamma,scale=0.1')
  lines(density(x),col='red',lwd=2)
  </code></pre>
  
  <p>Thanks!</p>