问题如下：
Company M purchased a $400,000 equipment with a 3-year useful life at the beginning of 2013, considering the salvage value is zero. The equipment was depreciated on double-declining balance method throughout its useful life. If compamy M shifts to straight-line method at the beginning of 2014, the annual depreciation expense of 2015 tends to be:
选项：
A.stay the same
B.smaller than before
C.greater than before
解释：
C is correct. Under double-declining balance method, the depreciation expense is the highest in the first year, then the expense tends to decline. If company M shifts to straight-line method at the beginning of 2014, the depreciation expense of 2014 and 2015 will be equal, which means the depreciation expense of 2014 is lower than before and that of 2015 is higher than before.
以下是戴老师的回答
M公司在2013年年初购买了一个价值400，000的设备，年限是3年，使用加速折旧法，残值是0
那么第一年的折旧就是400,000*（2/3）=266,667
第二年的折旧就是{（400,000-266,667）*（2/3）=88,,893
第三年折旧就是折44440，因为没有残值
如果第二年换成了直线折旧法，折旧就是（400,000-266,667）/2=66667
第三年也是66667
你看直线折旧法下的第二年的折旧费用是不是低于加速折旧法
但是第三年直线折旧法的费用是大于加速折旧法的
原版书上R28的example 8很详细的对比了折旧方法，你可以看一下
第三年的折旧不应该是44440，而是44440X2／3吧？
