Question

How do you find the limit of `(x / cos (-3x))` as x approaches `-oo`?

Answer 1

The limit does not exist

Explanation:

It should be clear that the denominator oscillates between `+-1`, and the demonstrator decreases without bound as `x rarr -oo`,

Hence the function increases without bound as `x rarr -oo`,

This can be verified with the graph of the function:
graph{x/cos(0-3x) [-80, 80, -40, 40]}