已知:sin(x+7π/6)=—1/4,求sin(x+7π/6)+cos^2 (23π/6 -x)的值

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已知:sin(x+7π/6)=—1/4,求sin(x+7π/6)+cos^2 (23π/6 -x)的值
已知:sin(x+7π/6)=—1/4,求sin(x+7π/6)+cos^2 (23π/6 -x)的值

已知:sin(x+7π/6)=—1/4,求sin(x+7π/6)+cos^2 (23π/6 -x)的值
sin(x+7π/6)=-1/4
sin(x+π+π/6)=-1/4
sin(π+x+π/6)=-1/4
-sin(x+π/6)=-1/4
sin(x+π/6)=1/4
sin(x+7π/6)+cos^2 (23π/6 -x)
=-1/4+cos^2 (4π-π/6 -x)
=-1/4+cos^2 (-π/6 -x)
=-1/4+cos^2 (π/6+x)
=-1/4+1-sin^2 (π/6+x)
=3/4-(1/4)^2
=12/16-1/16
=11/16