title: C++ - Trouble understanding easeInOutSine
body: <p>I am trying to understand this easing formula:</p>
  
  <pre><code>float easeInOutSine(float t, float b, float c, float d)
  {
      return -c/2 * (cos(M_PI*t/d) - 1) + b;
  };
  </code></pre>
  
  <p>Here are what the variables equal:</p>
  
  <p>t: current time
  b: start value
  c: change in value
  d: duration</p>
  
  <p>I am trying to apply this to a sprite transformation and am confused about what exactly needs to be passed in.</p>
  
  <p>If I wanted for instance to move a ball from y = 0 towards y = 10 at 0.25 units per second, which values are which? What I am really looking for is another explanation of what these variables mean in relation to what I am after.</p>