To express the polar equation r = cos(2θ) in rectangular coordinates, we use the following conversion formulas: scss Copy code x = r cos(θ) y = r sin(θ) Substituting r = cos(2θ) into these formulas, we get: scss Copy code x = cos(2θ) cos(θ) = cos(θ) cos(2θ) y = cos(2θ) sin(θ) = sin(θ) cos(2θ) Therefore, the rectangular equation in terms of x and y is: scss Copy code x = cos(θ) cos(2θ) y = sin(θ) cos(2θ) So, the rectangular equation of the polar equation r = cos(2θ) is x = cos(θ) cos(2θ) and y = sin(θ) cos(2θ).