I have tried to train a neural network for a simple x^2 function    I developed training data in excel. First column (X) is =RANDBETWEEN(-5,5) i.e random integer between -5 and 5Second column simply squares first columnAnd third column, my output 'y' column is 0 or 1. 0 if second column is less than 12.5 else 1I made 850 training examples and used the first column as 'X' and third column as 'y'However I am only able to get a training accuracy of 63%!Where could I have gone wrong? I changed input_layer to 1 and tried hidden units between 5 and 35. Tried regularization lambda 0 to 2 but still only 63% accuracy! Where could I have gone wrong?My predict function is p = 1 if h2(i)>0.5 else 0.Any help will be much appreciated! :-)I also noticed that my neural network's output is 0.3XXX for all training examples...how is this possible?? 
Applying neural network for simple x^2 function for demonstration purpose
machine learning;classification;neural network;beginner;octave