cos(π/12)cos(5π/12)=
化简cos(π/12)*cos(5π/12)
若cos(5π12
已知cos(5π12
计算cos(a+5π/12)cos(a+π/6)+cos(π/12-a)cos(π/3-a)
cos(π/32)*cos(π/16)*cos(π/8)=
1:COS(-7π/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.
已知cos(α+β)=12/13,cos(2α+β)=3/5,若β∈(0,π/2),求cosα的值.
cos(π/4+x)=3/5,17π/12
cos5/12πcosπ/12+cosπ/12sinπ/6=?
化简cos(π/12-α)-根号3cos(5π/12+α)