Compute Cost (for one variable)

ex1/computeCost.m

@@ -6,16 +6,18 @@ function J = computeCost(X, y, theta)
 % Initialize some useful values
 m = length(y); % number of training examples
 
-% You need to return the following variables correctly 
+% 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.
 
+predictions = X * theta;
+errors = predictions - y;
+squared_errors = errors .^ 2;
 
-
-
+J = 1/(2*m) * sum(squared_errors);
 
 % =========================================================================