sin(a+b)=56/65 求sin(a-b)急!题意应该没错！

sin(a+b)=56/65 求sin(a-b)急!题意应该没错！ 已知sin(a)=2sin(b)求sin(a/2)/sin(b/2)的值. 求 sin(a+b)=? 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 【证明】Sin A+sin B=2Sin 22 证明sin(a+b)sin(a-b)=sin^2 a-sin^2 b, 如何证明sin(a+b)sin(a-b)=sin*a-sin*b (*为平方) 求证恒等式sin(A+B)sin(A-B)=sin²A-sin²B 求证:sin(a+b)sin(a-b)=sin^2a-sin^2b 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), cos(a+b)=sin(a-b) 求tan a 已知角ab sin(a+b)=-3/5 sin(b-π/4)=12/13 求cos(a+π/4)) 答案是-56/65 已知角ab sin(a+b)=-3/5 sin(b-π/4)=12/13 求cos(a+π/4)) 答案是-56/65 sin a-sin b等于 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