title: Function for polynomials of arbitrary order (symbolic method preferred)
body: <p>I've found polynomial coefficients from my data:</p>
  
  <pre><code>R &lt;- c(0.256,0.512,0.768,1.024,1.28,1.437,1.594,1.72,1.846,1.972,2.098,2.4029)
  Ic &lt;- c(1.78,1.71,1.57,1.44,1.25,1.02,0.87,0.68,0.54,0.38,0.26,0.17)
  NN &lt;- 3
  ft &lt;- lm(Ic ~ poly(R, NN, raw = TRUE))
  pc &lt;- coef(ft)
  </code></pre>
  
  <p>So I can create a polynomial function:</p>
  
  <pre><code>f1 &lt;- function(x) pc[1] + pc[2] * x + pc[3] * x ^ 2 + pc[4] * x ^ 3
  </code></pre>
  
  <p>And for example, take a derivative:</p>
  
  <pre><code>g1 &lt;- Deriv(f1)
  </code></pre>
  
  <p>How to create a universal function so that it doesn't have to be rewritten for every new polynomial degree <code>NN</code>?</p>