(坐标系与参数方程选做题)在极坐标系中,过点 ( 2 , π 4 ) 作圆 ρ=

2025-04-24 23:14:28
推荐回答(1个)
回答1:

∵点P (
2
π
4
)
,∴ x=
2
cos
π
4
=1
y=
2
sin
π
4
=1
,∴P(1,1).
∵圆 ρ=
2
,化为普通方程:
x 2 + y 2
=
2
,即x 2 +y 2 =2.
∵点P(1,1)满足圆的方程,∴点P在圆上.
K OP =
1
1
=1

∴过点P的圆的切线的斜率K= -
1
K OP
=-1,
∴过点P的圆的切线方程为y-1=-(x-1),即为x+y-2=0.
故答案为x+y-2=0