Calculate the cube root of a number
Haskell - 35

c n=(iterate(\x-&gt;(x+n/x/x)/2)n)!!99


Example runs:

c 27  =&gt;  3.0
c 64  =&gt;  4.0
c 1  =&gt;  1.0
c 18.609625  =&gt;  2.6500000000000004  # only first 4 digits are important, right?
c 3652264  =&gt;  154.0
c 0.001  =&gt;  0.1
c 7  =&gt;  1.9129311827723892
c (-27)  =&gt;  -3.0
c (-64)  =&gt;  -4.0


Moreover, if you import Data.Complex, it even works on complex numbers, it returns one of the roots of the number (there are 3):

c (18:+26)  =&gt;  3.0 :+ 1.0


The :+ operator should be read as 'plus i times'