化简求值cos(π/7)cos(2π/7)cos(4π/7)

化简求值cos(π/7)cos(2π/7)cos(4π/7) COS(π/7)+COS(3π/7)+COS(5π/7)化简求值, 求数学高手帮忙cos(2π/7)+cos(4π/7))+cos(6π/7)=?(化简求值) cos(3π/2 - π/3),求值 高一三角函数 化简求值[sin(7π/2+a)*cos(a-π)*sin^2 (a+2π)]/[cos(3/2+π)*tan(π+a)*cos^3(-a-π)] 求值:cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11) 求值：cos(π/11)-cos(2π/11)+cos(3π/11)-cos(4π/11)+cos(5π/11) 求值:cosπ/7*cos2π/7*cos3π/7 cos(pai/15)×cos(2pai/15)×cos(3pai/15)×cos(4pai/15)×cos(5pai/15)×cos(6pai/15)×cos(7pai/15)求值 cos(pai/15)×cos(2pai/15)×cos(3pai/15)×cos(4pai/15)×cos(5pai/15)×cos(6pai/15)×cos(7pai/15)求值 已知cosα=√3/3,化简并求值:(1+(tan2α)^2)[cos(2α+π/3)+cos(2α-π/3)] 求值：cos²A+cos²（2π/3+A)+cos²(2π/3-A) 求值:cos(2pai/7)+cos(4pai/7)+cos(6pai/7)pai打不出,不好意思 倍角公式与和角公式化简或求值cos π/17 * cos 2π/17 * cos 4π/17 * cos 8π/17 sina(-2)+cos(-2-π)tan(2-4π)化简求值要步骤 化简求值1/2*sin2α-cos^2(π/4-α) 高中三角函数化简求值化简：√2-sin^2+cos4 （根号下） cos(π/9)*cos(2π/9)*cos(3π/9)*cos(4π/9） cos^6(π/8)-sin^6(π/8)=求值,[cos^2(π/8)-sin^2(π/8)][cos^4(π/8)+sin^4(π/8)+cos^2(π/8)sin^2(π/8)]=cos(π/4)[1-cos^2(π/8)sin^2(π/8)]=cos(π/4)[1-[sin^2(π/4)]/4]==7√2/16