Problem 3. (20 points) Suppose the following facts are given: . Sex (cos(x) + sin(ac) ) dac = ex sin(ac) . d(x cos(x)) = (cos(x) - x sin(a) ) dac . d(a sin(a) ) = (sin(ac) + ac cos(ac) ) dac Use these facts to calculate the integral xet cos(ac) dac. Hint: Integration by parts