更新1:
From step 1 to step 2 the absolute sign of w is removed, and step 3 to step 4 the absolute sign is also removed, but why and how do I know they can be removed?
In what situation can the absolute sign be removed?
回答 (1)
2017-10-02 7:12 pm
✔ 最佳答案
Because w, x could be any real number except 0.However, considering ln w and ln x, if w, x < 0, they are undefined. Therefore absolute signs were given.
收錄日期: 2021-04-23 18:34:46
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20170928134715AAcIdIX