Attention this is not a repeated talk, now why do we need iteration, they’re many iteration algorithms and some succeeded to make iterative usually with iteration iterative variables, this simply because y is function of the independent x and of the dependent y, i. e. depend on itself equation though, which x and y satisfy y=f(x,y), almost self behavior equation formula, more what if we need to integrate f, we do that as the solver with the process at aboelata.com, we solve any such formula or equation herein, we issue the exact solution, sometimes making things take place and happen.