title: How to Rotate vector
body: <p>I've been searching on tons of forums but nothing to work with (or understand). 
  So i have this </p>
  
  <pre><code>public void OnFinishCasting(Champion owner, Spell spell, Unit target)
      {
          var current = new Vector2(owner.X, owner.Y);
          var to = Vector2.Normalize(new Vector2(spell.X, spell.Y) - current);
          var range = to * 1150;
          var trueCoords = current + range;
  </code></pre>
  
  <p>And i will explain to you what it does.
  When i Press the Q button it shots a projectile in the mouse direction , What i need is to make another projectile and shot it in another direction like a cone or something , no matter where it goes , just rotate it how i like.
  How to do it ? </p>