How to solve the following nonlinear system of equations ???
mm = 10; h = 1/mm; nn = 10000; k = 0.1/nn;
(*initial condition*)
Table[w[i, 0] = N[Sin[\[Pi]*i*h]], {i, 0, mm}];
(*boundary condition*)
Table[w[0, j] = 0, {j, 0, nn}];
(*boundary condition*)
Table[w[mm, j] = 0, {j, 0, nn}];
(*varables*)
vars = Table[w[i, j], {i, 1, mm - 1}, {j, 1, nn}] // Flatten;
(*equations*)
eqs = Table[(1 + (2 k)/h^2) w[i, j + 1] == (
w[i + 1, j] + w[i - 1, j])/2 -
k/h (w[i + 1, j]^2 - w[i - 1, j]^2) -
k/h^2 (w[i + 1, j] + w[i - 1, j]), {i, 1, mm - 1}, {j, 0,
nn - 1}] // Flatten;
(*solution*)
sol = Flatten[NSolve[eqs, vars, Reals]];