Which of the following could be a coterminal angle for -5pi/4?

19pi/4
7pi/4
-17pi/4
-25pi/4

I've done my math twice, but I can't seem to get the right answer:( pls help?

3 answers

coterminal means a complete circle (s) away

2π is a full circle ... 8π/4 in this case

-5π/4 ± n(8π/4) ... n is an integer value
This ends up giving me 3pi/4, which is what I've been getting... at this rate I'm pretty sure I'm going something wrong, I don't know what to do from here.
what if n=3 ?