Question

What is the range of the function `y = sec x`?

Answer 1

Since `y=secx=1/cosx` and since the range of the function `y=cosx` is `[-1,1]`, than the range of the function `y=secx` is `(-oo,1]uu[1,+oo)`.

You can see also the graph:

graph{secx [-10, 10, -5, 5]}