Chapter 9 - Trigonometric Identities, Models, and Complex Numbers - 9.2 Identities, Expressions, and Equations - Exercises and Problems for Section 9.2 - Exercises and Problems - Page 363: 16

$$2\sec ^2\left(θ\right)$$

Simplifying the expression using trigonometric identities, we find: $$\frac{1}{1-\sin \left(θ\right)}+\frac{1}{1+\sin \left(θ\right)} \\ \frac{2}{\left(-\sin \left(θ\right)+1\right)\left(\sin \left(θ\right)+1\right)} \\ \frac{2}{\cos ^2\left(θ\right)} \\ 2\sec ^2\left(θ\right)$$