calculate this.. I am having some doubts.

The force of interest is given by 3/8 (0.02 + 0.005t 8(t) = 0.05 10.06 t 8 a) Derive an expression in terms of t, for the accumulated amount at time t, of 1 invested at t=0. [4] b) Find the present value at t=3 of 6,000 due at t=9. [3] c) Calculate equivalent level annual effective rate of interest implied by the transaction in b). [2] d) Calculate the accumulated value at t=9 of a continuous payment stream paid from t=1 until t=3 at rate of p(t)=20+5t. [4]