How do you convert #x^2 – 9 = 0# into polar form? Trigonometry The Polar System Converting Between Systems 1 Answer KillerBunny Nov 27, 2015 #r^2 = 9cos^2(theta)# Explanation: Since #r=xcos(theta)#, you have that #x=r/cos(theta)#. Take the square and substitute, and you'll get #r^2/cos^2(theta) - 9=0# which you can rewrite as #r^2 = 9cos^2(theta)# Answer link Related questions How do you convert rectangular coordinates to polar coordinates? When is it easier to use the polar form of an equation or a rectangular form of an equation? How do you write #r = 4 \cos \theta # into rectangular form? What is the rectangular form of #r = 3 \csc \theta #? What is the polar form of # x^2 + y^2 = 2x#? How do you convert #r \sin^2 \theta =3 \cos \theta# into rectangular form? How do you convert from 300 degrees to radians? How do you convert the polar equation #10 sin(θ)# to the rectangular form? How do you convert the rectangular equation to polar form x=4? How do you find the cartesian graph of #r cos(θ) = 9#? See all questions in Converting Between Systems Impact of this question 1494 views around the world You can reuse this answer Creative Commons License