gradient descent seems to fail

Question

I implemented a gradient descent algorithm to minimize a cost function in order to gain a hypothesis for determining whether an image has a good quality. I did that in Octav

Answer 1

This should work:-

theta(1,1) = theta(1,1) - (alpha*(1/m))*((X*theta - y)'* X(:,1) ); 

theta(2,1) = theta(2,1) - (alpha*(1/m))*((X*theta - y)'* X(:,2) );