title: plot solution of fsolve() of parametric function
body: <p>I have a function <code>f(v,u)</code> and I defined function</p>
  
  <pre><code>solutionf(u) := fsolve(f(v,u)=v);
  </code></pre>
  
  <p>I need to plot <code>solutionf(u)</code> depending on <code>u</code> but just</p>
  
  <pre><code>plot(solutionf(u), u = 0 .. 0.4e-1)
  </code></pre>
  
  <p>gives me an error </p>
  
  <pre><code>Error, (in fsolve) number of equations, 1, does not match number of variables, 2
  </code></pre>
  
  <p>However I can always take the value <code>solutionf(x)</code> at any <code>x</code>.</p>
  
  <p>Is there simple way to plot this? Or I have to make own <code>for</code> loop over <code>u</code>, take value at every point and plot interploating values?</p>