Question

1. \sec \frac{\pi}{2}

Explanation:

Step1: Recall secant definition

$\sec x = \frac{1}{\cos x}$

Step2: Substitute $x=\frac{\pi}{2}$

$\sec \frac{\pi}{2} = \frac{1}{\cos \frac{\pi}{2}}$

Step3: Evaluate $\cos \frac{\pi}{2}$

$\cos \frac{\pi}{2} = 0$

Step4: Analyze the expression

$\frac{1}{0}$ is undefined.

Answer:

Undefined