Question

直线xcosa+ysina+1=0,a∈(0,90°)的倾斜角是_____________

Answer 1

xcosa+ysina+1=0

则k=-cosa/sina=-tana

a∈(0,90°)

所以倾斜角是钝角

tana/2=1/2,tana=2tan(a/2)/(1-tan^2(a/2))=4/3

所以直线的方程为

y-2=4/3(x+1)