Hi,
I have my own sample data, and code computes to w =11,b=-13 . Next step plotting: contour graph looks correct but w dotted line is fixed to 200 and b dotted line is fixed to 100 which is similar from the exercise sample data.
Please advice,
Hello @Jignesh_Patel,
For us to see what you saw, please share a screenshot of the contour plot as well as the code that ran that plot out.
Raymond
Hello @Jignesh_Patel,
Thanks for sharing the screenshots! Now I get a grasp of your situation. Since you are exploring the code, let’s take a look at the plt_contour_wgrad function which makes the plot:
My steps 1, 2, 3, 4 show the traceback of how the two dotted lines were drawn. Two functions are used: hlines, and vlines, and you may google, for example, “vlines matplotlib” for documentation.
Once you figure out the logic, I am sure you will know what extra parameters you need to pass into plt_contour_wgrad for the dotted lines to behave as expected.
Good luck!
Raymond
PS: @Jignesh_Patel, I can imagine that it might be helpful to upload the notebook, but it is generally not permitted by the code of conduct in this place, even though it is an optional lab, and so I had asked for some screenshots. I wanted to take this chance to communicate this with you, and I look forward to seeing your continuous engagement in this community! Please keep trying, experimenting, and learning! Cheers. 
Thanks Raymond for prompt reply and encouragement, let me investigate on the items you shared and will get back to your with more details and outcome