How do you convert r = 1/(8 - cos(theta)) r=18cos(θ) into rectangular form?

1 Answer
Dec 7, 2015

8sqrt(x^2+y^2)-x=18x2+y2x=1

Explanation:

In converting between polar and rectangular forms:
color(white)("XXX")r=sqrt(x^2+y^2)XXXr=x2+y2
and
color(white)("XXX")cos(theta)=x/r = x/(sqrt(x^2+y^2))XXXcos(θ)=xr=xx2+y2

Therefore, given
color(white)("XXX")r = 1/(8-cos(theta))XXXr=18cos(θ)

We have
color(white)("XXX")r = 1/(8-x/r)XXXr=18xr

color(white)("XXX")r= 1/((8r-x)/r)XXXr=18rxr

color(white)("XXX")r= r/(8r-x)XXXr=r8rx

color(white)("XXX")8r-x=1XXX8rx=1

color(white)("XXX")8(sqrt(x^2+y^2))-x = 1XXX8(x2+y2)x=1