想問下點解 一個range square 左後, 會出左0 既
e.g. -1<= sinx <=1
square 左後會變左 0< sinx <= 1
我唔明呢個concept 呀
唔識解釋一下~~
關於inequality
2008-04-03 2:59 am
回答 (2)
2008-04-03 9:30 pm
✔ 最佳答案
Consider the two cases where -1 <= sinx <0 and 0<=sinx <1.If 0<= sinx <=1,
Afetr squaring, 0<= sin2x <=1
If -1<= sinx < 0,
After squaring, 1 >= sin2x > 0
Therefore, in general,
0 <= sin2x <= 1
2008-04-03 4:01 am
所有數square 都係正數
所以冇左負
square 左應該係會變左 0< sin^2 x <= 1
所以冇左負
square 左應該係會變左 0< sin^2 x <= 1
收錄日期: 2021-04-23 17:50:19
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