/sci/ - Science & Math

>>8962385
I am trying to understand the solution to this exercise.

I think I get it all the way until the end. How can you guarantee that you can choose such an [math] x_0 [/math]? Can you even guarantee that the o(1) term will be smaller than b-a?

That said, if someone could explain the entire argument that would be good too because... maybe the reason I don't get that final part is because I am not truly getting the parts before.