I am really stuck with this question

Given that $\displaystyle cosec\theta = -\sqrt 2$

and $\displaystyle tan \theta = -1$

and $\displaystyle -\pi<0<\pi$

find the exact value of $\displaystyle \theta$ in radians. Justify your answer.

I keep trying to find the relationship by rearranging $\displaystyle cosec$ in terms of $\displaystyle cot$ and then $\displaystyle tan$ but i'm not making any headway.

I feel like I'm missing something really obvious. Can anyone point me in the right direction??

Thanks