Answer
See graph, Limacon without inner loop, symmetric with respect to the polar axis.
Work Step by Step
1. See graph for $r=4-cos\theta$, it is a Limacon without inner loop.
2. Test symmetry with respect to the polar axis, replace $\theta$ with $-\theta$, we have $r=4-cos(-\theta)=4-cos\theta$, thus it is symmetric with respect to the polar axis.
