Question

sina=-8/17,a∈(3π/2,2π),求sin(π/6+a)

Answer 1

由已知得到cosa=15/17,

所以sin(π/6+a)=sinπ/6cosa+cosπ/6sina=15/34+(-8/17)*二分之根号三=（15-8倍根号3）/34