If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Polar functions

# Tangents to polar curves

AP.CALC: FUN‑3 (EU), FUN‑3.G (LO), FUN‑3.G.1 (EK), FUN‑3.G.2 (EK)

## Problem

Consider the polar curve r, equals, 2, cosine, left parenthesis, theta, right parenthesis for 0, is less than or equal to, theta, is less than, pi.
At which values of theta does the graph of r have a horizontal tangent line?