Polar coordinates r=a+b cos(θ), 0≤θ≤2π

Case 1: If b=0, circle centre (0,0) and radius =|a| Case 2: If a=0, circle centre (0,|b|/2) and radius =|b|/2 Case 3: If |a|<|b| and a ≠ 0, limacon with inner loop containing the origin Case 4: If |a|>|b| and b ≠ 0, limacon with no inner loop Case 5: If |a|=|b| and a ≠ 0, cardioids (heart-shaped) Complicated to understand But make it easier using GEOGEBRA