证明sin(a+b)-sina=2sinb/2*cos(a+b/2)

证明sina sin(a+2b) - sinb sin(b+2a) =sin(a+b)sin(a-b) 懂得进.证明,sina+sin(a+b)+sin(a+2b)+...sin(a+nb)=sin(a+ab/2)sin[(n+1)b/2]/sin(b/2) 证明三角函数等式sin(A+B)-sinA=2cos(A+B/2)sin(B/2) 证明sin(a+b)sin(a-b)=(sina+sinb)(sina-sinb) 证明sin(2a+b)/sina-2cos(a+b)=sinb/sina 证明sin(2a+b)/sina-2cos(a+b)=sinb/sina 【证明】Sin A+sin B=2Sin 22 如何证明sin(A-B)*sin(A+B)=sinA²-sinB² 证明sin(a+b)sin(a-b)=sin^2 a-sin^2 b, tan(A+B)=2tanB 证明3sinA=sin(A+2B) tan(A+B)=2tanB 证明3sinA=sin(A+2B)笑嘻嘻 如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2) 证明sin(a+b)-sina=2sinb/2*cos(a+b/2) sinb/sina=cos(a+b),证明3sinb=sin(2a+b) 证明:sin(2a+b)/sinb-2cos(a+b)=sinb/sina急 sinA(cos(2A+B)+cosB)=cosA(sin(2A+B)-sinB)证明 sinA+sinB-sinC=4sin(A/2)sin(B/2)cos(C/2)证明上式 怎么证明2sinA*cosA=sin(2A)