Is this graph valid ? Asking becouse of returning tendency on x axis. Never have seen it before, but in common sense it shoul work - knowing you can travel backwards…
And if vaild, can you do all the operation taught in this part of course - like counting the content under the graph, gradient etc.? I assume yes, can imagine how with content under the graph, don’t know about gradient… Guess there would be something like negative sign?
Thanks for any discussion.
