A fund starts with a zero balance at time zero. The fund accumulates with a varying force of interest $\backslash$delta $\_($t$)=(2$t$)/($t$^(2)+1),$t$>0.$ A deposit of $$100,000$ is made at time two. Calculate the number of years from the time of deposit for the fund to double. Possible Answers $\mathrm{.}51\mathrm{.}01\mathrm{.}52\mathrm{.}03\mathrm{.}0$