title: Solving equations in R similar to the Excel solver parameters function
body: <p>I have a question concerning the possibility to solve functions in R, and doing the same using excel.</p>
  
  <p>However I want to do it with R to show that R is better for my colleagues :)</p>
  
  <p>Here is the equation:</p>
  
  <pre><code>f0&lt;-1e-9
  t_pw&lt;-30e-9
  a&lt;-30.7397582453682
  c&lt;-6.60935546184612
  
  P&lt;-1-exp((-t_pw)*f0*exp(-a*(1-b/c)^2))
  </code></pre>
  
  <p>I want to find the <code>b</code> value for <code>P&lt;-0.5</code>. In Excel we can do it by selecting P value column and setting it to 0.5 and then by using the solver parameters function.</p>
  
  <p>I don't know which method is the best? Or any other way to do it?</p>
  
  <p>Thankx.</p>