suupose y= (2sin x-1 ) ^2 +3 where 0 < X < 360 (0度細過 or等於 x or 細過360度 )
find the max value of y and the corresponding values of x
find the values of x if y=3
ans
y=12 when x=270 degree
30 or 150 degree
maths .......................快
2008-05-18 10:22 pm
回答 (1)
2008-05-19 12:51 am
✔ 最佳答案
y= (2sin x-1 ) ^2 +3Since -1 ＜= sin x ＜= 1
The min value of 2sin x-1 is -3 when x=270
So at this time, y gets the max value (-3)^2+3=12
if y=3, then -3= (2sin x-1 ) ^2 +3
(2sin x-1 ) ^2 = 0
2sin x-1=0
sin x=1/2
x=30 or 150 degree
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