式子sin10π/3-根号2cos(-19π/4)-1/2tan(-13π/3)的值是
题目
式子sin10π/3-根号2cos(-19π/4)-1/2tan(-13π/3)的值是
答案
sin(10π/3)-√2cos(-19π/4)-1/2tan(-13π/3)
=sin(3π+π/3)-√2cos(19π/4)+1/2tan(13π/3)
=sin(3π+π/3)-√2cos(4π+3π/4)+1/2tan(4π+π/3)
=sin(π+π/3)-√2cos(3π/4)+1/2tan(π/3)
=-sin(π/3)-√2cos(3π/4)+1/2tan(π/3)
=-√3/2-√2*(-√2/2)+1/2*√3
=1
举一反三
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
最新试题
热门考点