Find the exact value of the trigonometric expression given t

Find the exact value of the trigonometric expression given that sin u = 5/13 and cos v = 15/17 (Both u and v are in Quadrant III.) cos(u + v)

sinu=-5/13

opposite=5 and hypotenuse=-13

Therefore adjacent=sqrt((-13)^2-5^2)=sqrt(144)=12

cos u= -12/13

cos v=-15/17

adjacent=15 and hypotenuse=-17

Therefore opposite= sqrt((-17)^2- 15^2)=sqrt64=8

sin v=-8/17

cos(u+v)= cos u cos v - sin u sin v=(-12/13)(-15/17) -(-5/13)(-8/17)

=(180/221) -(40/221)=140/221