title: Real cube root of a negative number
body: <p>I'm trying to see if there is a function to directly get the real cube root of a negative number. For example, in <a href="https://stackoverflow.com/questions/8290804/cube-root-of-a-negative-number">Java</a>, there is the <code>Math.cbrt()</code> function. I'm looking for the equivalent in R.</p>
  
  <p>Otherwise, my current hack is:</p>
  
  <pre><code>x &lt;- -8
  sign(x) * abs(x)^(1/3)
  </code></pre>
  
  <p>which is very inelegant and cumbersome to type every time. Thx!</p>