4. A fund grows by the force of interest ata-1 8(t) 1+ ta for t > 0, and where a, > 0. 100,000 is invested at time zero. The amount of interest earned in year one is 695.5550057, and the amount of interest earned in year two is 2178.175569. Find the equivalent annual effective interest rate over the interval (2, 4). 4. A fund grows by the force of interest ata-1 8(t) 1+ ta for t > 0, and where a, > 0. 100,000 is invested at time zero. The amount of interest earned in year one is 695.5550057, and the amount of interest earned in year two is 2178.175569. Find the equivalent annual effective interest rate over the interval (2, 4)