已知sin(a-pai/4)=1/3,则cos(a+pai/4)=?
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![已知sin(a-pai/4)=1/3,则cos(a+pai/4)=?](/uploads/image/z/4337661-21-1.jpg?t=%E5%B7%B2%E7%9F%A5sin%28a-pai%2F4%29%3D1%2F3%2C%E5%88%99cos%28a%2Bpai%2F4%29%3D%3F)
已知sin(a-pai/4)=1/3,则cos(a+pai/4)=?
已知sin(a-pai/4)=1/3,则cos(a+pai/4)=?
已知sin(a-pai/4)=1/3,则cos(a+pai/4)=?
sin(a-π/4)
=sin[(a+π/4)-π/2]
=-sin[π/2-(a+π/4)]
=-cos(a+π/4)
=1/3
cos(a+π/4)=-1/3