Excel help; I'm having problems with trying to get a working formula

2. The switch in the RC circuit in the figure below represents the shutter button of a digital camera. When the shutter is pressed at t=0, the capacitor releases its energy to the flash, represented by the resistor R, to generate a short but intense light. For the flash to function properly, its voltage should be at least 2.1V for at least 10msec. Your design shows that the voltage across the flash is v(t)=3e for t0, where R=80 and C=240F. a) Construct an Excel worksheet as shown below and write an Excel formula in cell E6 to calculate and display the voltage across the flash at t=0msec with the values entered for the given design parameters (i.e., R in cell B5 and C in cell B6). Make sure to properly use absolute and relative addresses. Copy and paste the formula written in cell E6 to cells E7 to E26 to complete the table. Make sure to check units! After completing the table, determine if the design meets the specifications and clearly indicate your answer on the worksheet using highlighted cells. b) While keeping C=240F, find the resistor value to have the flash on for at least 10msec. Use a separate tab from (a)