Question

r = 3secθ to rectangular form???

Answer 1

x^2+y^2+3y=0, right?

Answer 2

I would use x^2 + y^2 = r^2, x= r cos θ , y = r sin θ

in this case
r = 3 /cos θ

replace cos θ = x/r to get
r = 3/ (x/r)
r = 3r /x

cancel r from both sides
1 = 3/x
x = 3

Answer 3

Oh...

Answer 4

So for rsecθ = 3, is it x=-3?

Answer 5

r sec = 3

r/cos = 3
r / (x/r) =3
r^2 / x = 3
(x^2 + y^2)/x = 3

x^2 -3x + y^2 = 0

complete the square on the x terms, to make this look nicer (equation of a circle)