If $\displaystyle {\csc{\alpha}}=\frac{{7}}{{5}}$ such that $\displaystyle \alpha$ terminates in quadrant II and $\displaystyle {\cos{\beta}}=\frac{{3}}{{8}}$ such that $\displaystyle \beta$ terminates in quadrant IV then

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

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