Chapter 8 - Application of Trigonometry - Chapter 8 Test Prep - Review Exercises - Page 842: 95

$$r = 2\sec \theta {\text{ or }}r = \frac{2}{{\cos \theta }}$$

$$\eqalign{ & x = 2 \cr & {\text{Where }}r\cos \theta = x,{\text{ then}} \cr & r\cos \theta = 2 \cr & r = \frac{2}{{\cos \theta }} \cr & {\text{or}} \cr & r = 2\sec \theta \cr} $$