cosπ/5×cos2π/5
COSπ/5乘以COS2π/5
求COSπ/5*COS2π/5
cosπ/5·cos2π/5等于多少?
(cosπ/5)(cos2π/5)的值等于
cosπ/5 乘以cos2π/5等于多少
cosπ/5*cos2π/5 =(2sinπ/5*cosπ/5*cos2π/5)/(2sinπ/5) =(sin2π/5
(二倍角的三角函数)cosπ/5cos2/5π的值是______cosπ/5cos2π/5 =sinπ/5cosπ/5c
cos派/5cos2派/5
已知sin(π/4-α)=5/13,α∈(0,π/4) 求cos2α/cos(π/4+α)
cosπ/5乘以cos2π/5的值是多少?请给出具体解题过程,谢谢拜托各位大神
cosπ/5cos2π/5的值等于 :麻烦过程竖着写 横着写看不懂~最好一步一步写清楚~
已知sinα+cosα=1/5,且π/2≤α≤3π/4,求cos2α