i want to animate a graph (x^2) in this case, but it must begin from the x=0 to x=(constant), so it should show as a curve that is filling from x = 0 to x = constant
Like this?
Animate[Plot[x^2,{x,0,c},PlotRange->{{0,4},{0,16}}],{c,0,4}]
If that isn't what you are looking for and that with the documentation page for Animate
doesn't give you enough information to modify it to suit your needs then perhaps you can give more detail about what you are looking for and someone will be able to help you.