How to prove the following
If x, y and z are variables such that
(i) when x is constant, z proportional to y,
and
(ii) when y is constant, z proportional to x,
then z proportional to xy.
variation
2010-07-05 11:31 pm
回答 (1)
2010-07-06 12:02 am
✔ 最佳答案
(i) when x is constant, z proportional to y,we have z = ky * x ... (1) or x * z = ky ... (2) , were k is a constant;
(ii) when y is constant, z proportional to x,
we have z = kx * y ... (3) or y * z = kx ... (4) , were k is a constant;
We can see that only (1) = (3) ,
So z = k xy were k is a constant.
i.e. z proportional to xy.
收錄日期: 2021-04-16 13:30:00
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100705000051KK00787