把2sin^x+1>cos2x+2改成...
回答 (1)
2011-05-17 8:04 am
✔ 最佳答案
把2Sin^2 x+1>Cos2x+2改成為Cos2x<0?? Sol
2Sin^2 x=1－Cos2x
2Sin^2 x+1=2－Cos2x
2Sin^2 x+1>Cos2x+2
2－Cos2x>Cos2x+2
0> 2C os2x
0>Cos2x
收錄日期: 2021-04-23 23:23:40
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https://hk.answers.yahoo.com/question/index?qid=20110516000051KK01174