Question

sec function (secant function) is not defined for

• A. even multiple of $\frac{\pi}{2}$
• B. odd multiple of $\frac{\pi}{2}$
• C. even multiple of $\pi$
• D. odd multiple of $\pi$

Answer 1

Answer: (B)

Since, $\sec x=\frac{1}{\cos x}$, the domain of $y=\sec x$ is the set $R-\left\{x: x=(2 n+1) \frac{\pi}{2}, n \in Z\right\}$ and range is the set $R-(-1,1)$. It means that sec (secant function) assumes all real values except $-1 < y < 1$ and is not defined for odd multiples of $\frac{\pi}{2}$.