As best I can make out, you can't use equation editor, because OneNote
doesn't support object linking and embedding--you can't insert MS Draw
objects or spreadsheets or equations or anything as objects, only as pictures.
You can insert the equation into a Word document, copy it to the clipboard,
and paste it into ON, but it gets pasted as a picture, which means that if
you ever want to change it you have to start from scratch. If you have
MathType (equation editor is a watered down version of MathType) it will run
standalone, so you can enter an equation into MathType, copy it, and paste it
into ON, but it's still a picture.
I hope I'm missing something and that somebody who knows more about it than
I do will tell me I'm wrong. If I'm right, I hope MS will think about
supporting OLE in the next version of ON.
Elbert