If $\displaystyle {\cot{\alpha}}=\frac{{8}}{{5}}$ such that $\displaystyle \alpha$ terminates in quadrant III and $\displaystyle {\sin{\beta}}=\frac{{1}}{{8}}$ such that $\displaystyle \beta$ terminates in quadrant II then

 $\displaystyle {\tan{{\left(\alpha+\beta\right)}}}=$Preview Question 6  

Your answer should be exact but you do not have to rationalize your denominator.