特殊用法arc cosine1.反余弦arc-hyperbolic cosine1.反双曲余弦direction cosine1.方向余弦hyperbolic cosine1.双曲余弦（函数）integral cosine1.余弦积分inverse cosine1.反余弦logarithmic cosine1.对数余弦natural cosine1.余弦真数rised cosine1.上升余弦versed cosine1.余矢（函数）