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: 22

$$ tan(r^2-s^2)$$

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