若sinα>tanα>cotα(-π/2,π/2),则α的取值范围是() A(-π/2,-π/4) B(-π/4,0)
1个回答
若sinα>tanα,
即若sinα >sinα /cosα,
显然在(-π/2,π/2)上,1≥cosa>0,
故1/cosa ≥1,
所以如果sinα >sinα /cosα,则sinα
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