solve that,,,,plz

2007-11-11 8:31 pm
0<360

2sin^2 x+5sinx-3=0

help

回答 (3)

2007-11-11 8:37 pm
✔ 最佳答案
2sin^2 x+5sinx-3=0
(sinx+3)(sinx-1/2)=0
sinx=1/2 or sinx=-3(rejrcted)
sinx=1/2
x=30度 or 150度
2007-11-11 9:23 pm
2sin^2 x+ 5sinx -3 =0
(2sinx -1)(sinx +3) = 0
sinx = 0.5 or -3(rejected)
x=30度 or 180-30度
x=30度 or 150度
2007-11-11 8:40 pm
2sin^2 x+5sinx-3=0
(2sinx - 1)(sinx+3) = 0
sinx = 1/2 or sinx = -3(Because the range of sinx is 1 and -1 ,so sinx = -3 is rejected)
x = 30度 or 150度


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