机器学习（1）---线性回归（Linear Regression）

notation:

m = training example;

X = input variable/features

Y = output variable/"target" variable

(x,y) = training example

(xi,yi) the ith training example

living area ---- price

X1 = size  X2 = #badroom

Gradient Descent

PS：小编觉得，我觉得最好的就是梯度下降公式的推导了，希望对大家有帮助。