以知cos(a+β )=-1,求证sin(2a+β )+sinβ=0
问题描述:
以知cos(a+β )=-1,求证sin(2a+β )+sinβ=0
答
cos(a+b)=-1
sin(a+b)=0
sin(2a+b)+sinb=2(sin(a+b)*cosa)=0