【sin330°*tan(-13π/3)】/【cos(-19π/6)*cos690°】
【sin330°*tan(-13π/3)】/【cos(-19π/6)*cos690°】
[sin330°-tan(-13π/3)]/[cos(-19π/6)-cos690°]
cos(19π/6)+tan(16π/3)=?
cosπ/3+tanπ/4+3tan²π/6+sinπ/2+cosπ+sin3π/2等于?.
tan(-11π/6)、sin(-16π/3)、cos120°、cos(-180°-β)的求解过程.
sin(-21π/4) cos(-20π/3) tan(-19π/6)=
tan(13π/3)+sin(-5π/2)+cos(-23π/6)
求下列各三角函数值:(1)sin(-1920°) (2)cos(-1560°) (3)tan(-17π/6)
cos(6分之19π)tan(-3分之16π)
化简:[sin(π+α)*cos(π-α)*tan(π-α)]/[cos(π/2+α)*tan(3π/2-α)*tan(
求证cos(720°+α)(2/cosα+tanα)(1/cosα-2tanα)=2cosα-3tanα
若α∈(0,π/6) 比较tan(sinα),tan(cosα),tan(tanα)的大小