最速下降法和牛顿法，用最速下降法求解无约束问题: min f(x)和用阻尼牛顿法求解无约束问题: min f(x)等-Steepest descent method and Newton method, with the steepest descent method for unconstrained problem: min f (x) and unconstrained problems with damping Newton Method: min f (x), etc.