∵COS(2/3π-2X)=COS(2X-2/3π)=COS(2X+4/3π)=1-2SIN^2(X+π/3)=7/8
∴SIN^2(X+π/3)=±1/4
因为等于
-7/8
所以应该题目打错了
若COS(2/3π-2X)=-7/8,则SIN(X+π/3)=?
1个回答
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