Second Fundamental Theorem of Calculus:
If we have a function defined as
where is a continuous function, is a constant, and is a function of
Then the function (with respect to ) is given by:
Now on to your question. I will use B and C to be the same functions of A as you have:
Now we can apply the second fundamental theorem to each of those integrals since they are in the required form.
And now you can plug in B, B', C and C' in their right places. Is that the answer you're looking for?