inequality

solve 4x^3 >x
4x^3>x

i)當x>0,
4x^2>1
x^2>1/4
x>1/2 or x<-1/2(捨棄)

ii)當x<0,
4x^3>x
4x^2<1
x^2<1/4
-1/2< x <1/2
therefore,-1/2 < x < 0

therefore,-1/2 < x < 0 or x > 1/2

As follows:

圖片參考：http://i117.photobucket.com/albums/o61/billy_hywung/Jun07/YahooKnowledgeCrazyineq7.jpg


2007-06-21 08:51:22 補充：
唔用 tabulation 可以好似樓下o個位用 case method.無錯, 吾係差人.