Problem with Newton's method: An example

Course Q&A Math for Machine Learning Calculus for Machine Learning and Data Science
1

Hey DeepLearning.AI,

So with the video Newton’s method: an example, I think there’s a small error in the calculations:

Timestamp 1:50, I think the answer is 0.00275235295, not 0.097.

I did the calculations twice, plugging in the exact values in the video, and cannot reproduce 0.097.

X1 = 0.05 - ((e^0.05 - 1/0.05) / (e^0.05 + 1/0.05^2))
= 0.05 - ((1.051 - 20) / (1.051 + 400))
= 0.05 - (-0.0472)
= 0.00275 approximately

2

Hi @Wenxin_Liu.

It’s great practice that you did it by hand.

All your steps are correct except for the last line. As you evaluated the 3rd line, you forgot to cancel out the two minus signs making the expression a difference (0.05 - 0.0472 = 0.00275 approx) instead of a sum (0.05 + 0.0472 = 0.97 approx).

I hope that helps. Thank you!

1 Like
3

Ah yes, I made a mistake there. Thank you for pointing it out!