. . . . .
In the two above snippets I am wondering how "b)" was arrived at. In the question both parts of the equation show a plus and at "b)" one of the signs has changed to a minus symbol. I'm really not sure what is meant by generalizing to an arbitrary function as I am being asked to do.
Thanks in advance...
original images:
https://skydrive.live.com/redir?resid=D ... gpF0ko&v=3
https://skydrive.live.com/redir?resid=D ... yVVJws&v=3