求cos(-19/6∏)的值
求cos(-19/6∏)的值
cos(-519°)求三角函数的值
求cos(α+β)值的题目
1.已知tan(∏-α)=m^2 |cos(∏-α)|=-cosα求1/cos(∏+α)的值.
已知cos(x+∏/4)=1/3,求cos(2x)/cos(x-∏/4)的值(∏是圆周率)
求(sin^6α+cos^6α)/(sin^4α+cos^4α)的值
已知cos(π/6+x)=√3/3,求cos(5π/6-x)的值,
已知cos(13π/6+x)=根3/3,求cos(23π/6-x)的值
已知cos(π/6+θ)=根号3/3,求cos(5π/6-θ)的值
已知cos(π/6+a)=根号3/3求cos(5π/6-a)的值
已知cos(π/6-α)=根号3/3,求cos(5π/6+α)的值
已知cos(π/6+a)=根号3/3,求cos(7π/6+a)的值