(1/2sin2α)+(cos2α)=sinαcosα+cos^2α-sin^2α=(sinαcosα+cos^2α-sin^2α)/1=(sinαcosα+cos^2α-sin^2α)/(cos^2α+sin^2α)=(tanα+1-tan^2α)/(1+tan^2α)(分子分母同时除以cos^2α)=(6+1-36)/(1+36)= -2...