title: Draw Graph curves with UIBezierPath
body: <p>I'm drawing a graph in my application. My problem is that I want to draw line joining vertex points as curves. Currently I'm drawing them with <code>UIBezierPath</code>'s function <code>addLineToPoint:</code>. I want to draw them as curves. I'm well aware that <code>UIBezierPath</code> has following two functions to support this feature.</p>
  
  <p>Cubic curve:<code>addCurveToPoint:controlPoint1:controlPoint2:</code>
  Quadratic curve:<code>addQuadCurveToPoint:controlPoint:</code></p>
  
  <p>But problem is that I don't have control points. All i have is two end points. Neither I found a method/formula to determine control points. Can anyone help me here? I will appreciate if someone can suggest some alternative...</p>