find a formula for cos4x in terms of cosx .hence write down a quartic equation (ie an equation of degree 4) which has cos (pi/12) as r root . what are te other roots of your equation??
2. find all complex numbers z such that |z| =| z + square root 2 | = 1 .prove that each of these satisfies z^8 = 1.
leungjdhdg
2010-10-10 5:42 am
回答 (1)
2010-10-10 6:07 am
✔ 最佳答案
======================================================圖片參考：http://img89.imageshack.us/img89/4138/30036859.png
2010-10-09 22:07:59 補充：
http://img89.imageshack.us/img89/4138/30036859.png
收錄日期: 2021-04-23 23:22:57
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20101009000051KK01638