Plotting dot to denote a a specific point in a curve

Hello,

I was wondering how to plot a dot specifying a point along a curve that I'm plotting.

My code is the following:

x=-20:0.01:20;
    y=x.^5-4*x.^4+3*x.^2+8;
    y0=ones(1,length(x))*15;
    hold on;
    zoom xon; zoom yon;
    zoom on;
    plot(x,y);
    plot(x,y0, '--g', 'LineWidth',2),axis([-2 4,-80, 60]);

I want to plot on the intersection between the two plots. I know where it is located (using the zoom function allows me to easily find it) but I don't know the specific syntax required to put a dot there.

Any feedback would be greatly appreciated.

[Geoff Hayes]

Just use plot as you have done before using scalar inputs for the x and y coordinates rather than the vectors used previously.