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)
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