log( 2做底 ) [(4^x-2)-12] </= x-2
Help!
F.5 Maths! prove log ..
2009-05-18 1:08 am
回答 (2)
2009-05-18 1:59 am
✔ 最佳答案
呢題係prove或是solve x?2009-05-17 17:59:21 補充：
我當呢題係solve x去計:
圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/03-14.gif
2009-05-18 3:44 am
log( 2做底 ) [(4^x-2)-12] </= x-2
Log2[(4x-2)-12]<=x-2
Log2[(4x-2)-12]<= Log22 x-2
4 x-2-12<=2 x-2
(2 x-2)2-12<=2 x-2
(2 x-2)2-2 x-2-12<=0
(2 x-2-4)( 2 x-2 +3) <=0
(2 x-2-4) <=0 或 ( 2 x-2 +3) <=0
2 x-2<=4 或 2 x-2<=-3 (捨去)
2 x-2<=22
因此, x<=4
祝福你身心快樂!學業進步!
主恩滿溢!
Log2[(4x-2)-12]<=x-2
Log2[(4x-2)-12]<= Log22 x-2
4 x-2-12<=2 x-2
(2 x-2)2-12<=2 x-2
(2 x-2)2-2 x-2-12<=0
(2 x-2-4)( 2 x-2 +3) <=0
(2 x-2-4) <=0 或 ( 2 x-2 +3) <=0
2 x-2<=4 或 2 x-2<=-3 (捨去)
2 x-2<=22
因此, x<=4
祝福你身心快樂!學業進步!
主恩滿溢!
收錄日期: 2021-04-22 00:38:23
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090517000051KK01399