I am using Stewart's Concepts/Context 3. Its been 2 years since my first calculus class so I am a little rusty on interpreting graphs from f(x), f''(x)...ect.

I just do not understand the "K" concept of the Error bounds when trying to approximate an integral. I know it involves finding f''(x) which I have no problem finding, but it seemed as though my teach was just picking the largest constant in f''(x)...I have been to many web sites and they all get K is totally different ways.

I do not understand what |f ''(x)| <= K means. Why <= ? Help please