Vector Integrals, these must be turned into scalars to integrate. We will use these in all Maxwell's equations and the Biot Savart Law. 16. OX . dA = where X = 21 + 5j and dA = (-xi + y))dA over the square area (1, 1) to (5,5). 17. Simplify (don't solve) dixr = 73 where I and r are in the x-y plane given by X