title: Take sin of expression with units in sympy
body: <h1>The main problem</h1>
  
  <p>The problem is that when I take the sin of 30 degrees (with units) I can't use N to find a numeric answer. A minimum example is below.</p>
  
  <pre><code>from sympy import sin, N
  from sympy.physics.units import deg
  N(sin(30*deg))
  </code></pre>
  
  <p>So is there either</p>
  
  <ul>
  <li>A way to take the sin of something with units?</li>
  <li>Is there a simple quick way to remove the units?</li>
  </ul>
  
  <hr>
  
  <h1>Known partial solution</h1>
  
  <p>I am aware of the <code>.args</code> way of getting the numbers but my problem with that is that if I do something like </p>
  
  <pre><code>from sympy import sin, N
  from sympy.physics.units import deg, rad, convert_to
  number = convert_to(30*deg, rad)
  number.args
  </code></pre>
  
  <p>This will yield a <code>(1/6, pi, rad)</code>. But it can also yield a tuple with just two parts. So to separate everything out I need a whole other function.</p>