Example 1

We are playing with the way "Manipulate" works.

f[x_,h_,k_]:=(((x-h))^2)+k

Manipulate[Plot[f[x,h,k],{x,-3,3},PlotRange->{-5,10}],{k,-2,2},{h,-3,3}]

Example 2

This is our helix ... next time we will do it right the first time.

r[t_]:={Cos[t],Sin[t],t}

Manipulate[ParametricPlot3D[r[t],{t,0,h},BoxRatios->1,PlotRange->{{-1,1},{-1,1},{0,6π}}],{h,π,6π}]