Question

At which values of is the function y = sec theta undefined?

Answer 1

Given:

`\sec \theta=\infty`

To find the value of the angle:

It can be written as,

`\begin{gathered} \sec \theta=\infty \\ (1)/(\cos \theta)=\infty \\ \cos \theta=0 \\ \theta=\cos ^(-1)(0) \\ \theta=(\pi)/(2),(3\pi)/(2),(5\pi)/(2)\ldots\text{.} \end{gathered}`

Thus, the answer is,

`odd\text{ multiples of }(\pi)/(2)`

Hence, the correct option is D.