How to fit math function to the dataset in Python
<p>I have three sets of data as shown below:
<a href="https://i.stack.imgur.com/Cq9Ja.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Cq9Ja.jpg" alt="enter image description here"></a></p>

<p>I wonder what is the function they follow and how to fit these curves in Python?</p>

<p>I guess the first function is something like: </p>

<blockquote>
  <p>y = ax<sup>b</sup> + cx + d</p>
</blockquote>

<p>I tried some arbitrary parameters:</p>

<pre><code>x = numpy.arange(1,10000,2.)
a = 100.
b = -0.003 
c = 50.
d = 0.1
y = -a/x**d+b*x+c
scatter(x,y)
</code></pre>

<p>The figure shows like this:</p>

<p><a href="https://i.stack.imgur.com/3Seso.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3Seso.jpg" alt="enter image description here"></a></p>

<p>Anyone could help with the other two?</p>