已知-45°<α<135,sin(45°-α)=3/5,则cos2α/cos(45°+α)=?
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已知-45°<α<135,sin(45°-α)=3/5,则cos2α/cos(45°+α)=?
![已知-45°<α<135,sin(45°-α)=3/5,则cos2α/cos(45°+α)=?](/uploads/image/z/15702221-29-1.jpg?t=%E5%B7%B2%E7%9F%A5-45%C2%B0%EF%BC%9C%CE%B1%EF%BC%9C135%2Csin%2845%C2%B0-%CE%B1%29%3D3%2F5%2C%E5%88%99cos2%CE%B1%2Fcos%2845%C2%B0%EF%BC%8B%CE%B1%29%3D%3F)
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