Week4 Assignment 2 - Dead Kernel

You must have accidentally damaged some sections of your notebook. E.g. perhaps you have accidentally converted some of the “code” cells to “markdown” (non-executable). I suggest you do “Kernel → Restart and Clear Output” followed by “Cell → Run All”. Then carefully scan through the whole notebook to find the first point at which an error is thrown. That should be the place to start your investigation of what is wrong. Note that there are items on the notebook menus that allow you to toggle the “type” of a cell and there are “keyboard shortcuts” for doing that as well. So one theory is that you accidentally typed one of those keyboard shortcuts at an inopportune position.

Or if you prefer, the other approach is just to start with a “clean slate”: use the procedure on the FAQ Thread to get a clean copy of the notebook. Then very carefully “copy/paste” over just your completed code from the “YOUR CODE HERE” sections and see if that fixes things.