cos5/12πcosπ/12+cosπ/12sinπ/6=?
cos5/12πcosπ/12+cosπ/12sinπ/6=?
(sin5π/12-sinπ/12)(cos5π/12+cosπ/12)=?
(sin5π/12+cos5π/12)(sinπ/12-cosπ/12)
cos5π/12=sinπ/12
帮我解,证明恒等式(cos平方5π/12)+(cos平方π/12)+(cos5π/12)(cosπ/12)=5/4
数学,证明恒等式(cos平方5π/12)+(cos平方π/12)+(cos5π/12)(cosπ/12)=5/4.
求值cos5π/8*cosπ8
不查表求值:cos5π/12·sinπ/12=
cos方5π/12+cos方π/12+cosπ/12*cos5π/12 最后等于5/4的过程.
cos方5π/12+cos方π/12+cosπ/12*cos5π/12 最后等于4/5的过程.
为什么cos5π/12等于sinπ/12
已知cos(6π-α)=√3/3 求cos5/6π+α-sin²(α-π/6)的值