Question

What is the curve in which the polar subtangent is constant
(A) r(0+c)+a=0
(B) r(0-c)+a=0
(C) r(0+c)-a=0
(D) all of these​

Answer 1

Answer:

Correct option is

A

r(θ+c)+k=0

Let the constant length of the polar subtangent be a

Therefore as given in the question r

2

dr

dθ

=a

which is the differential equation of the required curve

To solve, put it into the form

dθ=a(

r

2

1

)dr⇒∫dθ=∫a(

r

2

1

)dr

⇒θ+c=−

r

a

⇒r(θ+c)+a=0