sin(a+pai/4)=根号2\4,求sin2a
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sin(a+pai/4)=根号2\4,求sin2asin(a+pai/4)=根号2\4,求sin2asin(a+pai/4)=根号2\4,求sin2acos(2a+pai/2)=1-2(sin(a+p
sin(a+pai/4)=根号2\4,求sin2a
sin(a+pai/4)=根号2\4,求sin2a
sin(a+pai/4)=根号2\4,求sin2a
cos(2a+pai/2)=1-2(sin(a+pai/4))^2=1-2*2/16=3/4
sin2a=-cos(2a+pai/2)=-3/4