Question

Evaluate the expression without using a calculator:
sec[arctan(-3/5)]

Answer 1

I got the answer as sort(34)/5, but should I put a +/- in front of it?

Answer 2

Yes, you should.

Answer 3

Would you be able to explain why?

Answer 4

Why the \pm part or the whole thing?

Answer 5

just the +/- part. I don't understand why it could negative or positive

Answer 6

One way to think about this is that both plus and the minus value satisfies the equation or not.

Answer 7

Yeah, I figured that out, but I thought there might have been a reason beyond that. I guess not. Thanks for the help!

Answer 8

Probably there is, but I can't at the top of my head. Anyways, you are welcome :)