解由公式cos2α=cos²α-sin²α
即cos²α-sin²α=cos2α
即cos^2π/6-sin^2π/6=cos2*π/6=cosπ/3=1/2
二倍角 cos^2*π/6-sin^2*π/6=?
1个回答
相关问题
-
4Sin π/2 －3Cos π/3 +6Sin3/2π － 6Cos π 计算
-
求值:2cosπ/2-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6+sin3π/
-
sin2π／3=?；cos2π／3=?；sin7π／6=?；cos7π／6=?说下
-
2sin（7π／6）cos(-π／6)=?
-
特殊角三角函数值0 π/6 π/4 π/3 π/2 2π/3 3π/4 5π/6 π 3π/2sin cos tanco
-
Cos(π+α)+6cos(-α)/sin(2π-α)+4sin(二分之π-α)+4sin(二分之π+α)=5
-
变式3（倍角）若x∈[0，π2]，sin(x−π6)＝35，求sin(2x+π6)的值．
-
sin^2a+cos^2(π/6+a)+1/2sin(2a+π/6)
-
Sin(π+π/6)Sin(2π+π/6)Sin(3π+π/6).Sin(2008π+π/6)
-
[2sin(π/12)sin(nπ/6)]/2sin(π/12)={cos[(2n-1)π/12]-cos[(2n+1)