text: Q:
  
  ContourPlot of an Implicit Function with a parameter
  
  Is it possible to use ContourPlot for an implicit function when another parameter is changing. 
  To be more precise, suppose we have a function of the form F[x,y,z]. Now for a fixed value of z=z1, we can use ContourPlot to plot the locus of points that satisfy F[x,y,z1]=0 by simply using
  Contourplot[F[x,y,z1]==0,{x,xl,xh},{y,yl,yh}]
  
  I wanted to see if there is a way to vary z1 and plot what happens.
  Thanks
  Ali
  
  A:
  
  Just use Manipulate:
  f[x_, y_, z_] := Cos[y + x^2 z]
  Manipulate[ContourPlot[f[x, y, z] == 0, {x, -5, 5}, {y, -5, 5}],
      {{z, 0}, -3, 3}]
  
  