4. Consider the polar curves C₁ r = 2 sin 0 and C₂ = 2 cos 0, where 0 ≤ 0 ≤ 2π. a) Find the Cartesian equations of C₁ and C2 and make a neat sketch of these curves. b) Using polar equations of C₁ and C₂ to find their intersection points (Do not use their Cartesian equations!). c) Using polar equations of C₁ and C₂ to show that they intersect each other at right angles (Do not use their Cartesian equations!).