引用:
原帖由 Alextung 於 2014-7-27 03:30 PM 發表 
名義利率≈實際利率+通脹率
但是事實上，名義利率=實際利率 + 通脹率 +（實際利率×通脹率）
我們不會考慮（實際利率x通脹率），因為它通常是非常小
我還是想知道什麼是（實際利率x通脹率）, 意味著 ...
This is a mathematical approximation problem, need not brother about it in HKDSE Economics.
(1 + c%) = (1 + a%)(1+ b%) = 1 + a% + b% + ab/10000.
c% ~ a% + b% (If a and b is small enough, ab/10000 can be neglected!)
For example,
If a and b is small enough, let's a = 5 and b = 5, ab / 10000 = 5 x 5 /10000 = 0.25%, So It can be neglected.
However, if a and b is not small enough, it cannot be ignored and the equation is not hold.
