title: Why SVG rotate about a point formula is reverse of normal formula？
body: <p>I am reading <code>SVG</code> Essentials, at chapter 6, it talk about the rotate transform. It says</p>
  
  <blockquote>
    <p>rotate(angle, centerX, centerY) is equal to translate(centerX, centerY) rotate(angle) translate(-centerX, -centerY)</p>
  </blockquote>
  
  <p>But What I learn before to calc this problem is first make point A(x,y) to A(x - centerX, y - centerY), then rotate, then add centerX, centerY back. </p>
  
  <p>Like <a href="https://stackoverflow.com/a/32376643/4263793">this answer</a> says.</p>
  
  <p>I try to review some linear algebra knowledge but still can't figure what's the different.</p>
  
  <p>Can any one tell me the why this happen?</p>
  
  <p>Kindly guide me why <code>svg</code> add-rotate-sub and normal is sub-rotate-add?</p>
  
  <p>Thank you in advance.</p>