tanπ/12+cotπ/12的值等于多少?2吧,为什么答案是4?
问题描述：
tanπ/12+cotπ/12的值等于多少?
2吧,为什么答案是4?
答
tanπ/12+cotπ/12
=sinπ/12/cosπ/12+cosπ/12/sinπ/12
=(sin²π/12+cos²π/12)/(sinπ/12cosπ/12)
=1/[1/2*sin(2*π/12)]
=1/(1/2*sinπ/6)
=2/(1/2)
=4