title: estimate the slope of the straight part in boltzmann curve
body: <p>I was working with one dataset and found the curve to be sigmoidal. i have fitted the curve and got the equation A2+((A1-A2)/1+exp((x-x0)/dx)) where: </p>
  
  <ul>
  <li>x0 : Mid point of the curve</li>
  <li>dx : slope of the curve</li>
  </ul>
  
  <p>I need to find the slope and midpoint in order to give generalized equation. any suggestions?
  <a href="https://i.stack.imgur.com/Xoa7u.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Xoa7u.png" alt="enter image description here"></a></p>