using the definition: .
Prove = is continuous at the point a=0.
given epsilon>0, pick delta , then given h with |h|<delta.
we have
does this look good? what shall write for
You can restrict your delta. If you let then it follows that .
Remember that is the length of your interval, and so by making sure you're restricting the interval so its length is less than 2.
Remember, you only care about how the function behaves in some neighborhood about your point, so this restriction is okay.