3sin^2(α)+2sin^2(β)=2sinαsin^2(α)+(2-2cos^2(α))+(2-2cos^2(β))=2sinαcos^2(α)+cos^2(β)=[sin^2(α)-2sinα+4]/2设sinα=t因为2sin^2(β)=2sinα-3sin^2(α)≥02t-3t^2≥02/3≥t≥0cos^2(α)+cos^2(β)=[...