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已知sinθ(π/3+α)=1/3,则cos(5π/6+α)=

题目详情
已知sinθ(π/3+α)=1/3,则cos(5π/6+α)=
▼优质解答
答案和解析
cos(5π/6+α)=cos[π/2+(π/3+α)]=-sin(π/3+α)=-1/3