Machine-Learning-exercises_finished andrew NG上的课程machine learning 的习题解答

andrew NG上的课程machine learning 的习题解答，这些习题对于机器学习入门还是非常有帮助的，值得学习。

function J = computeCost（X y theta）
%COMPUTECOST Compute cost for linear regression
%   J = COMPUTECOST（X y theta） computes the cost of using theta as the
%   parameter for linear regression to fit the data points in X and y

% Initialize some useful values
m = length（y）; % number of training examples

% You need to return the following variables correctly 
J = 0;

% ====================== YOUR CODE HERE ======================
% Instructions: Compute the cost of a particular choice of theta
%               You should set J to the cost.
Z = （X * theta - y）.^2;
J = sum（Z（:1）） / （2 * m）;
% =========================================================================

end

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