Why is the second term present? Assuming x has died as per the first term the guaranteed annuity is triggered then it should just be a whole of life annuity after. Here it shows y living for n years then reversionary annuity for x and y+n. I'm a bit confused
It's not as simple as that as the whole life annuity is different for each year of death of x. You need to look at Q9.21 and the text that follows in the course to get the full explanation.
