Four years ago a company bought a $1 million machine with an estimated useful life of 10 years. For accounting purposes, the machine is being depreciated in the amount of $100,000 annually. The machine is used to manufacture a particular product and has no alternative use of scrap value. The annual revenue generated from operating the machine is $650 000 and the annual cost of the factors of production, other than deprecation, employed to generate that revenue is #600 000. Should the company continue to operate the machine?

但是从阅读了第16节， opportunity cost includes implicit cost and explicit cost, and economic depreciation is part of implicit cost. 所以opportunity cost 应该是100000（机器贬值）implicit cost+600000运营费用 explicit cost才对，请高手回答

 For accounting purposes, the machine is being depreciated in the amount of $100,000 annually.

this cost is an accounting estimation, but not the ture cost. After 10 years, can you keep using the machine?

of course you can. If you want, you can depreciate the machine within one year, but you can still use it.

For accounting purposes depreciated is explicit cost, although it is not real cash flow.

Opportunity cost is that if you don't launch the project,the revenue that you can earn in other project.