Question

The graph of a limacon curve is given. Without using your graphing calculator, determine which equation is correct for the graph. a circular graph with an inner loop on the bottom
[-5, 5] by [-5, 5]
r = 2 + 2 sin θ
r = 3 + sin θ
r = 1 + 3 cos θ
r = 1 + 3 sin θ

Answer 1

The only equation that can produce a loop at the bottom is the one that has opposite sign non-zero values for r at π/2 and 3π/2. The last selection meets that requirement.

r = 1 + 3 sin(θ)