cos5π/12=sinπ/12
cos5π/12=sinπ/12
不查表求值:cos5π/12·sinπ/12=
为什么cos5π/12等于sinπ/12
(sin5π/12-sinπ/12)(cos5π/12+cosπ/12)=?
cos5/12πcosπ/12+cosπ/12sinπ/6=?
(sin5π/12+cos5π/12)(sinπ/12-cosπ/12)
sin5/12π×cos5/12π怎么算?
计算cos5分之π+cos5分之2π+cos5分之3π+cos5分之4π
例题9和10,我知道有解析,但就是看不懂,好像是公式吧,我想知道cos5π/12是怎么变成sin的,周期不是π/2吗,乘
已知cos(6π-α)=√3/3 求cos5/6π+α-sin²(α-π/6)的值
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.