说明：  学会不同搜索法（最速下降法，共轭梯度法，牛顿法，拟牛顿法）的计算步骤； 比较不同搜索法（最速下降法，共轭梯度法，牛顿法，拟牛顿法）的优缺点。
(Institute of the different search method (steepest descent method, conjugate gradient method, Newton method, quasi-Newton method) for calculating steps compare different search method (steepest descent method, conjugate gradient method, Newton method, quasi-Newton method) the advantages and disadvantages.)