TOPIC: Depreciation

I've been trying to learn more on formulas. I have been looking at the formulas package and not ready to spend another $30 at this time.
That being said, I noticed that the topic of depreciation is listed as covered there. I've gone through all of the videos and read the PMBOK and don't remember anything on depreciation at all. I looked in the index in the back of the PMBOK and nothing. I Google it and everything I'm seeing is 2011 at the most recent. Is this an old topic no longer needed? Or am I completely missing this in my studies somewhere?

Is this a topic I need to know for the exam?

Hi,

I have same concerns , i bought the formula package & there is many questions in the Formula 106 sample questions on this topic & i actually choose to ignor solving them & waste my time i hope i can find a reply where this come from in the PMP exam prep?