Question

.

Answer 1

http://www.analyzemath.com/polarcoordinates/polar_to_rectangular_eq.html

Answer 2

\[If~ r = 2 \cos \theta, \] ...and we remember that x=r cos theta, then multiplying both sides of this equation by r results in \[r*r = r^2=2*r*\cos \theta \] Note that r^2 in polar coordinates is equivalent to an expression in x and y in rectangular coordinates. What is that expression? Replace x cos theta by ' x '.
Making these substitutions will eliminate r and theta and leave you with an equation in x and y.

Answer 3

I'd suggest you then group the x terms together and the y terms together. Can you picture what shape is represented by this relation in x and y?

Answer 4

I agree with Math Male