Slope of Normal
( ii ) If , then normal at ( x , y ) is parallel to y-axis and perpendicular to x-axis .
( iii ) If then normal at ( x , y ) is parallel to x-axis and perpendicular to y-axis .
Length of Tangent and Normal ( i ) Length of tangent , PA = y cosec θ =
( ii ) Length of normal ,
( iii ) Length of subtangent ,
( iv ) Length of subnormal ,