I got y(t)=(0.02t+0.00075t^2+0.0033333t^(3/2))/t but need help with the rest

Suppose that the instantaneous rate of return is given by r(t) = 0.02 +0.005 + 0.0015t. (a) Find the yield rate y(t) = 1 freds g(t) = (b) If $2400 is invested at time 0, what is the accumulated value at T = 4? Accumulated Value = $ (C) If the accumulated value at time T = 4 is A = $1000, what is the present value of the investment (1.e. at time T = 0)? Present Value = $ (d) Consider the cash flows (payments) [C1, C2, C3] = [ $-300, $300, $300) at times [T1, T2, T3] = [0.5, 0.75, 1]. Determine the present value of the stream of cash flows. Present Value = $ Suppose that the instantaneous rate of return is given by r(t) = 0.02 +0.005 + 0.0015t. (a) Find the yield rate y(t) = 1 freds g(t) = (b) If $2400 is invested at time 0, what is the accumulated value at T = 4? Accumulated Value = $ (C) If the accumulated value at time T = 4 is A = $1000, what is the present value of the investment (1.e. at time T = 0)? Present Value = $ (d) Consider the cash flows (payments) [C1, C2, C3] = [ $-300, $300, $300) at times [T1, T2, T3] = [0.5, 0.75, 1]. Determine the present value of the stream of cash flows. Present Value = $