For the curve

MATHEMATICS · Subjective · AP · Calculus BC · Parametric, Polar, and Vector-Valued Functions · Parametric, Polar, and Vector-Valued Functions

Problem

For the curve

r=3\cos\theta

, classify the tangent (horizontal or vertical) and state the concavity (concave up or concave down) of the graph at

\theta=\frac{\pi}{4}