Math.atan gives an error in java programming
<p>i am using haversine formula in java programming (using eclipse). 
My problem is at the end of the equation where i get an error (atan is underlined) saying that "The method atan(double) is undefined for the type Math". </p>

<p>i dont know what is the problem. Does anyone have an idea?  </p>

<pre><code>    double angle = 45;
    double arctan = Math.atan(angle);
</code></pre>
