解下列問題

2007-02-02 2:53 am

If @ takes any real values,find the range of the values of y of each of the following functions.

y = l 2sin@ - 5 l

回答 (2)

2007-02-02 3:53 am

✔ 最佳答案

-1 <= sin@ <= 1

-2 <= 2sin@ <= 2

-7 <= 2sin@ - 5 <= -3

7 >= | 2sin@ - 5 | >= 3

7 >= y >= 3

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2007-02-02 3:18 am

y=l 2sin@ - 5 l
±y=2sin@ - 5
sin@=(y+5)/2 or (5-y/2)

-1≦(y+5)/2≦1
-2≦y+5≦2
-7≦y≦-3

-1≦(5-y)/2≦1
-2≦5-y≦2
7≧y≧3

since y＞0 so 7≧y≧3

參考: me

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