code in jupyter.

2. Given a triangle with vertices at the coordinates A(1,3),B(1,1),C(3,7) : (a) Find the lengths of the sides. (b) Use the Law of Cosines formula to find cos(BAC). NOTE the formula can be rewritten as cos(BAC)=2bcb2+c2a2 where a,b,c are BC,AC,AB respectively. (c) Confirm your answer by finding cos(BAC) by using the dot product formula to find the angle between a=AB=(2,2) and b=AC=2,4. NOTE that you found the magnitudes in part (a), and you can compute the dot product by just using arithmetic operations