In △ABC\triangle ABC△ABC, the side lengths are a=11a = 11a=11, b=13b = 13b=13, and c=21c = 21c=21. Determine the exact value of cos(A)+cos(B)+cos(C)\cos(A) + \cos(B) + \cos(C)cos(A)+cos(B)+cos(C).
1314\frac{13}{14}1413
1514\frac{15}{14}1415
1914\frac{19}{14}1419
2314\frac{23}{14}1423