Solve in Excel the following problem, using the numerical technique of the steepest descent, with the VBA code proposed in the chapter: min fug JðuÞ ¼ Z 1 0 u2 dt y_ ¼  y þ u with initial condition y(0) ¼ 4 and y(1) ¼ 0. (Hint: in this case, as y(1) ¼ 0, namely the state variable is bounded, and therefore we need to integrate numerically backward the state variable, while we integrate forward the costate variable. Launch the Solver first to set up the costate variable, such that y(0) ¼ 4 and then run the VBA steepest descent VBA program).