设cos(a-1/2b)=-1/9,sin(1/2a-b)=2/3,且π/2
问题描述:
设cos(a-1/2b)=-1/9,sin(1/2a-b)=2/3,且π/2
答
800
答
∵π/2
设cos(a-1/2b)=-1/9,sin(1/2a-b)=2/3,且π/2
800
∵π/2