cosπ/7cos2/7πcos4/7π=
2个回答
cos(π/7) cos(2π/7) cos(4π/7)
= - 1/8
相关问题
求值:cos[2π/7]+cos[4π/7]+cos[6π/7].
求值:Cos2/7π+Cos4/7π+Cos6/7π
求证cos2π/7+cosπ/3=cosπ/7+cos3π/7
求cos(2π/7)*cos(4π/7)*cos(6π/7)的值
已知cosπ/3=1/2,cosπ/5*cos2π/5=1/4,cosπ/7*cos2π/7*cos3π/7=1/8……
cos2π/7×cos4π/7×cos6π/7等于多少?3Q
cos(-79π/6) =cos(79π/6) =cos(12π+7π/6) =cos(7π/6) =cos(π+π/6
COS(π/7)+COS(3π/7)+COS(5π/7)化简求值,
cosπ/15 cos2π/15 cos3π/15 cos4π/15 cos5π/15 cos6π/15 cos7π/1
sin3/7π*cos2/5π-cos(-3/7π)*sin(-2/5π)