求arctan[cot(-4)]
问题描述：
求arctan[cot(-4)]
答
4-π/2
答
由tan(kπ+π/2-x)=cotx,(k为任意整数)
得cot(-4)=tan(kπ+π/2+4),
则arctan[cot(-4)]=arctan(tan(kπ+π/2+4))=kπ+π/2+4(k为任意整数).