sin(2a+b)/sina-2cos(a+b)=sinb/sina ==>左边=[sin(2a+b)-2cos(a+b)sina]/sina =[sina*cos(a+b)+sin(a+b)*cosa-2cos(a+b)sina]/sina =[sin(a+b)*cosa-cos(a+b)sina]/sina =sin(a+b-a)/sina=sinb/sina=右边
求证sin(2A+B)/sinA-2cos(A+B)=sinB/sinA
1个回答
相关问题
-
证明sin(2a+b)/sina-2cos(a+b)=sinb/sina
-
求证: sina+sinb=2sin[(a+b)/2]cos[(a-b)/2] cosa+cosb=2cos[(a+b)
-
求证sina-sinb=2cos(a+b)/2*sin(a-b)/2这个怎么证明?
-
求证:sin(a+b)cos(a-b)=sina*cosa+sinb*cosb
-
sinb/sina=cos(a+b),证明3sinb=sin(2a+b)
-
请教sin(a+b)-sina=2cos(a+b/2)sinb/2
-
sinA+sinB 怎么变成2sin[(A+B)\2]cos[(A-B)\2]
-
证明sin(a+b)sin(a-b)=(sina+sinb)(sina-sinb)
-
已知sinA+cosA=2sina,sinA*cosA=(sinb)^2,求证4(cos2a)^2=(cos2b)^2
-
求证:a*sinA-b*sinB=c*sin(A-B).