题目

cos（-4分之十七派） sin（-3分之26的派） 求这两个三角函数值

提问时间：2020-07-26

答案

cos(-17π/4)
=cos(-π/4-4π)
=cos(-π/4)
=cos(π/4)
=√2/2
sin(-26π/3)
=sin(-26π/3+8π)
=sin(-2π/3)
=-sin(2π/3)
=-sin(π-π/3)
=-sin(π/3)
=-√3/2