title: Evaluating trigonometric expressions in sympy
body: <p>Using python 2.7 with PyCharm Community Edition 2016.2.3 + Anaconda distribution.</p>
  
  <p>I have an input similar to :</p>
  
  <pre><code>from sympy import *
  
  x = symbols('x')
  f = cos(x)
  print (f.subs(x, 25))
  </code></pre>
  
  <p>The output is <code>cos(25)</code>, . Is there a way to evaluate trigonometric identities such as sin/cos, at a certain angle ? I've tried <code>cos(degrees(x))</code>, but nothing differs. Am I missing some crucial part of documentation or there really isn't a way to do this ? Ty for your help :)</p>