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Multiple Choice
Identify whether the given equation is that of a cardioid, limaçon, rose, or lemniscate. r=3+2cosθ
A
Cardioid
B
Limacon
C
Rose
D
Lemniscate
Verified step by step guidance
1
Step 1: Recognize the general form of the polar equation provided. The equation is r = 3 + 2cosθ. This is a polar equation where r is expressed as a function of θ.
Step 2: Compare the given equation to the standard forms of polar curves. For a limaçon, the general form is r = a + bcosθ or r = a + bsinθ, where a and b are constants.
Step 3: Analyze the values of a and b in the equation. Here, a = 3 and b = 2. Since a ≠ b, the curve does not form a cardioid (which occurs when a = b).
Step 4: Eliminate other possibilities. A rose curve has the form r = acos(nθ) or r = asin(nθ), which is not the case here. A lemniscate has the form r² = a²cos(2θ) or r² = a²sin(2θ), which also does not match the given equation.
Step 5: Conclude that the given equation represents a limaçon because it matches the general form r = a + bcosθ with distinct values for a and b.