Hello.

I am wondering how to break a line at an intersection and delete a portion of that line.
I have used AutoCAD and it offers the ability to break a line where it intersects another line, and then select which portion of that broken line to delete. I am hoping Inkscape offers the same capability.

Attached is an image of what I have done so far.

I'd like to create a view of a parabola with the left branch longer and going up higher than the right branch. It does not have to be exact, but good enough to illustrate a concept. So I used the arc tool to create an ellipse. and then drew a line through the ellipse at an angle. Now I'd like to delete everything above that line, including the line itself (or just the parts that extend past the arc. One way or the other, the arc will be closed eventually.)

How can this be done? I have selected the line and the arc, and tried to break them, but it is not working. Or perhaps I am not using these tools correctly. Any help is appreciated.

An ellipse is not a parabola and sadly not even approximately similar. There is a simple way to do this: draw a rectangle about the size you want your end result to be (not necessary to be precise at all) and with it selected call the extension Function Plotter which resides under Extensions/Render



The +0.1, if you are wondering, is to keep the rectangle from clipping the vertex of the parabola just slightly, if you use clip. I left it in there but it isn't necessary with these values... In fact, you can set the bottom of the rectangle to be y= -0.1 and avoid it entirely.
The high sample rate is likewise a little overkill. You can pick a much lower sample rate and after applying the extension use the to select the nodes in your curve and make them auto-smooth (from the 's control bar. The resulting inaccuracy is negligible.
Or you could use a high sample rate and afterward use the simplify command to remove a lot of nodes. I feel that using a high sample and then holding down cmd-L until you have just a few nodes is the most accurate method.

(While I'm being thorough you can use x*x instead of the pow(x,y) function. If I were writing a Python script I would have.)

Thank-you very much. I think the graphics are now all finished, and I have taken my latest blog post (address in Profile) out of draft mode. A few more small edits may be done to the math, but the bulk of the post is finished.