求值:sin(-31π/6)-cos(-10π/3)-sin11π/4

求值:sin(-31π/6)-cos(-10π/3)-sin11π/4 求值：sin(π/12)+cos(π/12) sin(π+π/6)-cos(π+π/4)cos(-π/2)+1求值 求值:2sinπ/6+sin3π/2-2cosπ+2sinπ/3 sin^a+cos^(π/6+a)+1/2sin(2a+π/6)求值 求值sin²x+cos²(π/6+x)+1/2sin(2x+π/6) 求值:cos(-6分之31π) 求值:sin的平方α+cosαcos(π/3+α)-sin的平方(π/6-α) 求值：sin(π/4)cos(19π/6)tan(21π/4)急! sin(x+π/6)=1/2,则cos(π/3-x)求值 求值：sin(-3分之19π）+cos(-6分之25π）=? sin²(π/8)-cos²(π/8)求值 求值sinπ/8乘cosπ/8过程 求值sinπ/8乘cosπ/8过程 cos^2(π/5)+sin^2(π/10) 求值 求值:sin(26π/3)+cos(-17π/4)= sin(-7π／6)求值 求值：(1-sin^6 x-cos^6 x)/(1-sin^4 x-cos^4 x)