1. ## HARD domain problem

What is the domain of the following vector?

f(t) = 6 sec ^ (2t) i + t/sqrt(t ^ 2 - 4) j

I know that a part of its domain is abs(t) > 2 but what about sec???

By the way, here's the domain my book gives but it doesn't make any sense to me.

"t" does NOT equal [pi(2n + 1)]/4 (equal sign crossed by a short line)

and...

abs(t) > 2

Cheers.

2. If $t=\frac{(2K+1)\pi}{4}$ then $\cos(2t)=0$ therefore $\sec(2t)$ is not defined.

3. I see. I must have had a mind block because that does make sense. Thank you.

But I'm kinda irritated because I find that it's very, very hard to determine an equation for that domain type................