Question

how to find 6 trig functions of -9pi/4

Answer 1

where is -9pi/4?

Answer 2

http://i.stack.imgur.com/r8uHr.gif <--- notice in the Unit Circle, which you should have

the pair of values shown there are the cosine, sine pair, or x,y values

as Loser66 said, find \(\bf -\cfrac{9\pi}{4}\) and use that pair values

Answer 3

also that \(\bf \cfrac{9}{4}\implies \cfrac{8}{4}+\cfrac{1}{4}\implies 2+\cfrac{1}{4}\)