详细证明Sin(A+B)≤SinA+SinB是错误命题

详细证明Sin(A+B)≤SinA+SinB是错误命题 证明sin(a+b)sin(a-b)=(sina+sinb)(sina-sinb) |sin(a+b)|小于等于|sina|+|sinb|的证明, 证明sina sin(a+2b) - sinb sin(b+2a) =sin(a+b)sin(a-b) 证明sin(2a+b)/sina-2cos(a+b)=sinb/sina 证明sin(2a+b)/sina-2cos(a+b)=sinb/sina 证明三角函数等式sin(A+B)-sinA=2cos(A+B/2)sin(B/2) 如何证明sin(A-B)*sin(A+B)=sinA²-sinB² 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) 如何证明sinA+sinB=2sin((A+B)/2)cos((A-B)/2) 证明:sin(2a+b)/sinb-2cos(a+b)=sinb/sina急 sinb/sina=cos(a+b),证明3sinb=sin(2a+b) sinA(cos(2A+B)+cosB)=cosA(sin(2A+B)-sinB)证明 证明下列恒等式：sin(a+b)*cos(a-b）=sina*cosa+sinb*cosb tan(A+B)=2tanB 证明3sinA=sin(A+2B) 证明sin(a+b)-sina=2sinb/2*cos(a+b/2) tan(A+B)=2tanB 证明3sinA=sin(A+2B)笑嘻嘻 已知-∏/6≤B≤∏/4,3sin^2 a-2sin^2 b=2sina,求sin^2 b-1/2sina的最小值.过程尽量详细~