## Trigonometry (11th Edition) Clone

$\sec{(-x)} = \sec{x}$. Please refer to the step-by-step part for the complete solution.
RECALL: (1) The cosine function is an even function, which means $\cos{(-x)} = \cos{x}$ for all numbers in its domain. (2) $\sec{x} = \dfrac{1}{\cos{x}}$ Therefore, $\sec{(-x)} \\=\dfrac{1}{\cos{(-x)}} \\=\dfrac{1}{\cos{x}} \\=\sec{x}$ Thus, $\sec{(-x)} = \sec{x}$