普ez4HIzX我前段时间选了一款，真心不错~hKV今年春季新式时尚品牌实用更巧搭JnT_dpL-fGL/jianshenche?_Y87170164516341681420sina=2t/(1 t^2)asint bcost=(a^2 b^2)^(1/2)sin(t r)sina=2t/(1 t^2)cosa=(1-t^2)/(1 t^2) 半角公式编辑本段令tan(a/2)=tcosr=a/[(a^2 b^2)^(1/2)]tan(a/2)=(1-cos(a))/sin(a)=sin(a)/(1 cos(a))sin^2(a/2)=(1-cos(a))/辅助角公式sinr=b/[(a^2 b^2)^(1/2)]cosa=(1-t^2)/(1 t^2)cos^2(a/2)=(1 cos(a))/2sin^2(a/2)=(1-cos(a))/2asint bcost=(a^2 b^2)^(1/2)sin(t r)令tan(a/2)=辅助角公式cos^2(a/2)=(1 cos(a))/21
南瓜囡囡
