求 sin(a+b)=?

求 sin(a+b)=? 已知sin(a)=2sin(b)求sin(a/2)/sin(b/2)的值. cos(a+b)=sin(a-b) 求tan a 已知3SIN^2A+2SIN^2B=5SINA,求SIN^2A+SIN^2B范围 sin^2 A=sin^2 B+sinBsinC+sin^2 C 求A角 sin(a+b)=根号3/2,求a+b? sin(a)=5/13.a+b=45度,求sin(b).如题. 已知sin(A+B)=2/3,sin(A-B)=1/5.求tanA/tanB 已知sin(a+b)=1/2,sin（a-b)=1/3,求tana/tanb sin(a-b)=1,sin a=1/3,求cos b的值RT sin(a-b)=1 ,sin a=1/3 ,求cos b的值 已知SIN A=0.6275,SIN B=0.0547,求A,B的度数 sin(a+b)=56/65 求sin(a-b)急!题意应该没错！ 已知sinA=1/5,求2sin(A+B)cosA-sin(2A+B) 为什么cos2A-cos2B=-2sin(A+B)*sin(A-B),求推导公式 sin A+sin b=sinc（cos a+cos b）求三角形是什么形状? 已知sin(a+B)sin(a-B)=1/3,求cos2b-cos2a 3sin(a)^2+2sin(b)^2=1,3sin(a)=2sin(b),a,b都为锐角,求a+2b的值是3sin(2a)=2sin(2b),