Please help How do you graph the polar equation r=8-secθ ?

1 Answer
Aug 10, 2018

See the explanation and graphs.

Explanation:

As sec values (1,1),

r=8secθ(1+8,1+8)=(7,9)

r is periodic,with period 2π.

Short Table, for $theta in θ[0,π], sans asymptotic

π2and32π:

(r,θ): ( 7, 0 ) ( 6.845, pi/6 ) ( 6, pi/3 ) ( oo, pi/2 )#

(9.155,56π)(10,2π3)(9,π).

r=0,atθ=1.4455 rad.

The graph is symmetrical about θ=0.

graph is outside the annular ( circular ) region # 7 < r < 9 ).

Converting to the Cartesian form, using

(x,y)=r(cosθ,sinθ)and0x2+y2=r,

(x2+y2)0.5(1+1x)=8,

The Socratic graph is immediate, with asymptote x = 0.
graph{((x^2 + y^2)^0.5(1+1/x) - 8)(x+0.01y)=0[-40 40 -20 20]}
See the bounding circles r=7andr=9.
graph{((x^2 + y^2)^0.5(1+1/x) - 8)(x^2+y^2-49)(x^2+y^2-81)=0[-20 20 -10 10]}