2sin^a+3sina-2=0,求锐角a.

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2sin^a+3sina-2=0,求锐角a.2sin^a+3sina-2=0,求锐角a.2sin^a+3sina-2=0,求锐角a.2sin²a+3sina-2=0(sina+2)(2sin

2sin^a+3sina-2=0,求锐角a.
2sin^a+3sina-2=0,求锐角a.

2sin^a+3sina-2=0,求锐角a.
2sin²a+3sina-2=0
(sina+2)(2sina-1)=0
所以sina=-2或者sina=1/2
因为正弦函数的值域为[-1,1]
所以sina=-2舍弃
所以sina=1/2
a=30°

10

由3(sina)^2+2(sinb)^2=1--->3(cosa)^2+2(cosb)^2=4(1) 3sin2a-2sin2b=0(2) 代入(1)、(2)消去2b cos(a+2b)=cosa*cos2b-sina*sin2b