If sin α = 513 and sin β = 45 then the value of cos α cos β - sin α sin β is

If sin α = 513 and sin β = 45 then the value of cos α cos β - si

1.	If sin α = 513 and sin β = 45 then the value of cos α cos β - sin α sin β is
Answer» If sin $α$ = $\frac{5}{13}$ and sin $β$ = $\frac{4}{5}$ then the value of cos $α$ cos $β$ - sin $α$ sin $β$ is