求直线x·sinπ/7+y·cosπ/7+1=0的倾斜角
问题描述:
求直线x·sinπ/7+y·cosπ/7+1=0的倾斜角
答
x·sinπ/7+y·cosπ/7+1=0
y=(-sinπ/7/cosπ/7)x-1/cosπ/7
k=-sinπ/7/cosπ/7
=-tanπ/7
=tan(π-π/7)
=tan6π/7
所以倾斜角是6π/7