title: Exponential and linear model in the same plot with ggplot2
body: <p>I want to plot a linear model and an exponential model in the same plot. I've tried this code</p>
  
  <pre><code>qplot(mpg,wt,data=mtcars)
  + stat_smooth(method="lm", se=FALSE)
  + stat_smooth(method="lm", formula=log(y)~x, se=FALSE)
  </code></pre>
  
  <p>and I get this plot
  <img src="https://i.stack.imgur.com/VuYih.jpg" alt="enter image description here"></p>
  
  <p>but I want the exponential model plotted in the original y scale, not in the log(y) scale. </p>