There are many different algorithms for finding roots of equations. How familiar are you with numerical methods? Which numerical method would you use? What kind of function is in A2?


Newton-Raphson method is pretty easy to program when there's only one variable changing, assuming the function can be readily differentiated.
A bisection type algorithm is another that I have used that isn't too difficult to program, but you have to be able to give the algorithm two starting points, one on each side of the root.