please show all work, solve #2 only

1.000 (2) A continuously paying level annuity pays $50 each year for ten years. The force of interest is (5 +t)-!. Find the present value of this annuity. (3) An annuity is continuously varying and payable for ten years. The rate of payment at time t is (2 + +)and the force of interest is (1 + t) uolue of this annuity